Valve control system and method

ABSTRACT

A sprayer control system includes a plurality of smart nozzles each having at least one control valve with a valve operator, an electronic control unit for the valve operator, and one or more spray nozzles. The at least one control valve and the ECU control a flow rate of liquid agricultural product through the nozzles. A duty cycle modulator is in communication with the ECU and generates an applied duty cycle for the at least one control valve. The duty cycle modulator includes a specified duty cycle input having a specified duty cycle and a pressure monitor associated with the at least one control valve. A pressure comparator compares the valve pressure determined with the pressure monitor with a system pressure and generates a pressure error. An applied duty cycle generator generates the applied duty cycle based on the specified duty cycle modified by the pressure error.

CLAIM OF PRIORITY

This patent application is a continuation of U.S. Pat. ApplicationSerial No. 17/224,955, entitled “VALVE CONTROL SYSTEM AND METHOD,” filedApr. 7, 2021, which claims the benefit of priority of Krosschell et al.U.S. Pat. Application Serial No. 17/001,539, entitled “VALVE CONTROLSYSTEM AND METHOD,” filed Aug. 24, 2020 (Attorney Docket No.2754.276US1), and PCT Patent Application No. PCT/US2020/047696, entitled“VALVE CONTROL SYSTEM AND METHOD,” filed Aug. 24, 2020 (Attorney DocketNo. 2754.276WO1), which applications claim priority to U.S. ProvisionalPat. Application Serial No. 62/911,045, entitled “VALVE CONTROL SYSTEMAND METHOD,” filed on Oct. 4, 2019 (Attorney Docket No. 2754.276PRV),which applications are hereby incorporated by reference herein in theirentirety.

TECHNICAL FIELD

This document pertains generally, but not by way of limitation, toagricultural equipment.

BACKGROUND

An agricultural product (e.g., a fertilizer, carrier fluid, or the like)is optionally applied to a crop (e.g., one or more plants located in afarm field). In some examples, the agricultural product is applied witha sprayer system, for instance a sprayer mounted on a prime mover (e.g.,a tractor, truck, all-terrain-vehicle, or the like). The sprayer systemincludes a valve, and the valve facilitates application of agriculturalproduct to the crop (e.g., by spraying the agricultural product from anozzle). In some examples, the valve is operated by a controller, forinstance to translate the valve between an open position and a closedposition. In the open position, the valve permits flow of theagricultural product through the valve. In the closed position, thevalve does not permit flow of the agricultural product through the valve(e.g., between a valve inlet and a valve outlet). In some examples, thecontroller modulates the valve according to a duty cycle. The valveopens (or closes) in correspondence to the duty cycle of the modulationprovided by the controller.

OVERVIEW

The present inventors have recognized, among other things, that aproblem to be solved can include accurately applying an agriculturalproduct to a crop. In an example, a valve controls the flow of a fluidthrough the valve. The valve is included in a sprayer system thatapplies the agricultural product to the crop (e.g., by spraying theagricultural product from a nozzle). In some examples, the valve isoperated by a controller, for instance to translate the valve between anopen position and a closed position. In the open position, the valvepermits flow of the agricultural product through the valve. In theclosed position, the valve does not permit flow of the agriculturalproduct through the valve (e.g., between a valve inlet and a valveoutlet).

In an example, the valve is operated for a specified duty cycle. Thespecified duty cycle optionally corresponds to a time duration between afirst time interval when the controller modulates the valve (e.g., bygenerating a control signal) and a second time interval when thecontroller stops modulating the valve (e.g., by stopping the generationof the control signal). An actual duty cycle of the valve differs fromthe specified duty cycle for the valve. For instance, the mechanicalresponse of the valve (e.g., to begin translating the valve toward theopen position from the closed position) to the modulation provided bythe controller does not perfectly correspond in time to when thecontroller intends for the valve to modulate. In an example, the actualduty cycle of the valve corresponds to a time duration between a thirdtime interval when the valve actually begins transitioning between theopen position and the closed position, and a fourth time interval whenthe valve actually completes the transition between the open positionand the closed position. Accordingly, the specified duty cyclecorresponds to a time duration that the controller modulates the valve(e.g., the time duration that the controller generates a control signal,or the like). The actual duty cycle of the valve corresponds to the timeduration that the valve is in an open position (e.g., when a seal isdisengaged from a valve seat to allow flow through the valve) inresponse to the modulation provided by the controller. The actual dutycycle varies from the specified duty cycle, for example due tomechanical tolerances of the valve, operating conditions (e.g., highpressure as opposed to low pressure), inertia of mechanical componentsof the system, signal processing delays or the like.

In some examples, the valve is operated to deliver a specified amount ofagricultural product (e.g., a specified volume, specified flow rate, orthe like) through the valve. In some approaches, an actual amount ofagricultural fluid flowing through the valve differs from the specifiedamount because of differences between the specified duty cycle and theactual duty cycle of the valve. Accordingly, in some approaches theagricultural fluid is misapplied to the crop (e.g., too muchagricultural product, too little agricultural product, or the like), andthe misapplication affects one or more characteristics of the crop(e.g., growth, development, yield or the like).

The present subject matter can help provide a solution to this problem,such as by providing a system for applying agricultural product. Thesystem includes a valve, and the valve optionally includes a solenoidhaving a coil configured to generate a magnetic flux. In some examples,the valve includes a moveable valve operator, and the valve operatortranslates with respect to the coil based on the generated magneticflux. The valve operator optionally translates between a closed positionand an open position according to a specified magnetic flux associatedwith a specified duty cycle, for instance the valve (ideally) opens withapplication of the magnetic flux and closes with arresting of themagnetic flux. In an example, the valve operator prevents flow throughthe valve in closed position, and the valve operator permits flowthrough the valve in the open position.

In an example, the system includes a dissipation element, such as atransient voltage suppression diode (“TVS”), having a dissipationcharacteristic (e.g., an amount of energy dissipated in proportion to avoltage across the dissipation element). In some examples, thedissipation element dissipates energy from the coil to arrest themagnetic flux and thereby initiate a rapid closing of the valveoperator. For instance, a clamping voltage of a coil is increased andthe energy in the coil (the increased voltage) is readily dissipatedwith the TVS. The dissipated energy corresponding initiates a rapid dropoff in current and thereby decreases the magnetic flux that is based oncurrent.

In some examples, the system includes a controller, and the controllerreceives measurements of one or more electrical characteristics of atleast one of the coil or the dissipation element. The controlleroptionally determines an actual duty cycle of the valve operator usingthe measured electrical characteristics (e.g., through flux andelectrical characteristics caused by movement of the operator relativeto the coil). In an example, the controller determines a magnetic fluxcorrection (e.g., for the coil, or the like) based on a differencebetween the actual duty cycle and the specified duty cycle of the valveoperator. The controller optionally operates the valve operatoraccording to the specified magnetic flux and the magnetic fluxcorrection to guide the actual duty cycle of the valve operator towardthe specified duty cycle of the valve operator.

Accordingly, the system for applying an agricultural product facilitatesaccurate and precise application of the agricultural product to a crop.For example, the controller guiding the actual duty cycle of the valveoperator toward the specified duty cycle increases the accuracy (andprecision) of an amount of agricultural fluid to the crop. For example,the system facilitates the application of a specified amount ofagricultural product at a specified location (and/or at a specifiedtime). Accordingly, agricultural product is accurately and preciselyapplied to the crop, for example to improve one or more cropcharacteristics (e.g., growth, development, yield or the like) andminimize waste of the agricultural product (e.g., waste due tomisapplication).

This overview is intended to provide an overview of subject matter ofthe present patent application. It is not intended to provide anexclusive or exhaustive explanation of the invention. The detaileddescription is included to provide further information about the presentpatent application.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, which are not necessarily drawn to scale, like numeralsmay describe similar components in different views. Like numerals havingdifferent letter suffixes may represent different instances of similarcomponents. The drawings illustrate generally, by way of example, butnot by way of limitation, various embodiments discussed in the presentdocument.

FIG. 1 illustrates a perspective view of an example of an agriculturalsprayer.

FIG. 2 illustrates a schematic of an exemplary nozzle control system.

FIG. 3 illustrates a detailed schematic view of an exemplary nozzlecontrol system.

FIG. 4 illustrates an example of a valve, according to an embodiment ofthe present subject matter.

FIG. 5 illustrates an example of a valve, according to an embodiment ofthe present subject matter.

FIG. 6 illustrates an example of a system for applying an agriculturalfluid including a controller, according to an embodiment of the presentsubject matter.

FIG. 7 illustrates a representation of one or more drive signals used toapply a specified duty cycle to a valve and the resultant waveformshapes that are monitored by the controller, according to an embodimentof the present subject matter.

FIG. 8 illustrates an example diagram of duty cycle guidance.

FIG. 9 illustrates an algorithm for determining one or more duty cycles,for example a duty cycle corresponding to a time duration for the valveoperator transition between the closed position and the open position,according to an embodiment of the present subject matter.

FIG. 10 illustrates an algorithm for determining one or more dutycycles, for example a duty cycle corresponding to a time duration forthe valve operator transition between the open position and the closedposition, according to an embodiment of the present subject matter.

FIG. 11 illustrates an algorithm for compensating for variability usinga moveable valve operator position or a magnetic flux correction,according to an embodiment of the present subject matter.

FIG. 12 FIG. 12 illustrates a block diagram of an example machine uponwhich any one or more of the techniques discussed herein may perform,according to an embodiment of the present subject matter.

FIG. 13 illustrates a schematic diagram of an example of a system formodulating one or more of valves, according to an embodiment of thepresent subject matter.

FIG. 14 illustrates a detailed schematic view of an exemple nozzlecontrol system showing pressure variation along the boom

FIG. 15 illustrates an example of a duty cycle modulator configured tocompensate for valve performance or pressure errors.

FIG. 16 illustrates a block diagram of a method for controlling one ormore spray nozzles with duty cycle compensation.

DETAILED DESCRIPTION

FIG. 1 illustrates a perspective view of an example of an agriculturalsprayer 100. In an example, the agricultural sprayer 100 includes areservoir tank 102 and one or more sprayer booms 104. The sprayer booms104 optionally include one or more nozzles 106. In some examples, theagricultural sprayer 100 includes one or more electronic control units(ECU) 108 (e.g., a microprocessor based system), and for instance amaster node 110. (e.g., a microprocessor based system)

In an example, the reservoir tank 102 is integral with a prime mover 112(e.g., a tractor, truck, combine, vehicle, or the like). In someexamples, the reservoir tank 102 is a towed behind the prime mover 112(e.g., the reservoir tank 102 is included with a trailer, or the like).The reservoir tank 102, in an example, includes an agricultural productmixed with a carrier fluid, such as water. In some examples, the carrierfluid and the agricultural product are mixed in-line prior to or at thesprayer boom 104. The nozzles 106 are positioned along the sprayer boom104 to deliver the agricultural product (and the carrier fluid) to acrop (e.g., vegetables, fruit feed, or the like), for instance a croplocated in an agricultural field 114. Crops include, but are not limitedto, any product grown in an agricultural field, such as row and non-rowbased crops. Agricultural products include, but are not limited to,fertilizers, water, pesticides, fungicides, herbicides, or the like.

The agricultural sprayer 100 includes one or more controllers 116, forexample the ECU 108 and the master node 110. In an example, the masternode 110 operates in conjunction with the one or more ECU 108 to controldelivery of the agricultural product from the reservoir tank 102, to thesprayer boom 104 and the associated nozzles 106 for delivery to theagricultural field or crop.

FIG. 2 illustrates a schematic of an exemplary nozzle control system200, wherein the one or more nozzles 106 located on the boom 104 controla respective nozzle flow rate of an agricultural product dispensed fromthe nozzle 106. As shown in FIG. 2 , the master node 110 iscommunicatively coupled to one or more valves (e.g., the PWM valve 206)of the boom 104, such that system pressure within the boom 104 can becontrolled by the master node 110. In some examples, the master node 110of the current system is not configured to control the flow rate withinthe system 200, boom 104, or at the smart nozzles 106. Instead, themaster node 110 controls the pressure within the system 200, boom 104,or at the smart nozzles 106, and the pressure control provides controlof the flow rate (e.g., control to a lower pressure decreases flow whilecontrol to a higher pressure increases flow). The master node 110 is incommunication with a master flowmeter 202, a master pressure transducer204, and a master pulse width modulation (PWM) valve 206. The masternode 110 controls the master PWM valve 206 to provide a targeted systempressure (through modulated operation of a system pump associated withthe master PWM valve 206), such that a desired droplet size of theagricultural product is generated at the nozzles 106. For example,environmental conditions, such as wind, humidity, rain, temperature,field characteristics, or user preference determine whether a smaller orlarger droplet size of the agricultural product is preferred. Bycontrolling a targeted system pressure (e.g., maintaining, changing withvariations in flow rate or the like), the preferred droplet size ismaintained with the system 200.

In the exemplary embodiment, each of the nozzles 106 is a smart nozzlethat includes an electronic control unit (ECU) (e.g., ECU 108, shown inFIG. 1 or the like) that regulates, determines, and/or controls thenozzle flow rate of the agricultural product dispensed from the nozzle106, as discussed in reference to FIG. 3 . In other embodiments, a groupof the nozzles 106 are associated with a common ECU and is collectivelyconsidered a single smart nozzle. The smart nozzles 106 are connectedto, for example, the boom 104 and communicatively coupled to acontroller area network (e.g., nozzle CAN bus 208, wireless network orthe like) of the overall control system 200. As discussed herein, theCAN bus 208 is configured to distribute overall system information fromthe master node 110 (e.g., master node). The ECU at each smart nozzle106 uses data from the overall system information to regulate,determine, and/or control the nozzle flow rate of each correspondingsmart nozzle 106.

The master node 110 controls one or more of a system pressure or systemflow rate using, for example, the master pressure transducer 204 (or inother examples the flow meter, flow meter and pressure transducertogether or the like) and the master pulse width modulation (PWM) valve206. Although FIG. 2 illustrates a PWM valve as a master valve 206,embodiments are not so limited. For example, the master valve 206includes any valve capable of controlling pressure or flow rate of asystem, such as a ball valve, PWM valve, butterfly valve or the like.For instance, the master node 110 maintains the system pressure or flowrate at a target system value (e.g., a target system pressure or targetsystem flow rate). In another example, each smart nozzle 106 controlsthe component flow rate to the constituent nozzles associated with eachsmart nozzle. In another example, the master node controls the systempressure or system flow rate to one or more target values and the smartnozzles 106 control the flow rate for each of the constituent nozzles(e.g., one or more) associated with each smart nozzle. Collectively, thesmart nozzles 106 may control the overall agricultural product flow rateof the system.

In an example, the target system pressure is provided by a user, such asat the user interface 210 connected to the master node 110 by the nozzleCAN bus 208. In an additional example, the user also provides a targetsystem flow rate (e.g., volume/area) at the user interface 210. In anexample, the master node 110 provides one or more of the target systemflow rate or the target system pressure to each of the one or more smartnozzles 106, such that each smart nozzle 106 (or each ECU, as discussedherein) determines an individual agricultural product flow rate (orpressure) for the smart nozzle 106. For example, the system target flowrate is divided by the number of nozzles 106 to provide a targetagricultural product flow rate for each of the one or more nozzles 106.In an example, the master node 110 measures the flow rate (e.g., volumeper time) with a master flow meter 202 and compares it with the overalltarget flow rate (e.g., designated by one or more of the user, croptype, soil characteristic, agricultural product type, historical data,or the like). The master node 110 is configured to determine adifference or error, if present, between the measured system flow rateand the target system flow rate. In such an example, the master node 110provides the determined difference, by the nozzle CAN bus 208, to theindividual nozzles 106 (or ECUs, as discussed herein). The one or morenozzles 106 receive the difference on the CAN bus 208 and adjust theirpressure/flow/duty cycle curve using the difference (e.g., compensatingfor errors in the system) to reduce the error between the measured andtarget system flow rates (or reduce the error between the measured andtarget system pressures).

Additionally, in at least some examples, the master node 110 reports theactual pressure, measured by the master pressure transducer 204, as wellas boom 104 information, including, but not limited to, one or more ofyaw rate, speed, number of smart nozzles of the boom, distance betweensmart nozzles on the boom, to the smart nozzles 106 (or ECUs, asdescribed herein) for individual flow rate control (or pressure control)of each of the smart nozzles 106. For example, the information providedfrom the master node 110 is used in addition to nozzle characteristicsto control the individual flow rate control of each smart nozzle 106.Nozzle characteristics include, but are not limited to, one or more ofnozzle position on a boom, length of the boom, nozzle spacing, targetflow rate for the system (e.g., one or more of carrier fluid, injectionproduct, agricultural product of the mixed carrier fluid and injectionproduct, or the like), target pressure for the system (e.g., one or moreof carrier fluid, injection product, agricultural product of the mixedcarrier fluid and injection product, or the like), yaw rate of the boom,yaw rate of the agricultural sprayer, speed of the agricultural sprayer,one or more of the overall system pressure or flow rate (e.g., actualpressures or flow rates of the carrier fluid, injection product, mixedagricultural product or the like), agricultural product characteristics,valve performance such as a moveable valve operator transition time(including differences between specified and actual duty cycles), or thelike.

The system 200 is configured for installation on an agricultural sprayer(e.g., the agricultural sprayer 100, shown in FIG. 1 ). In an example,the sprayer moves during operation (e.g., translates, rotates,accelerates or the like). The system optionally adjusts flow rates atone or more of the smart nozzles, concentrations of injection productsdelivered by the smart nozzles, or the like. Accordingly, the systemprovides a consistent application pattern of agricultural product to thecrop. In another example, the one or more nozzle characteristics aredynamic and, and in some examples, the delivery of agricultural productby the nozzles is dynamic in correspondence with the nozzlecharacteristics. For instance, one or more of flow rates, pressures orthe like through nozzles associated with a smart nozzle 106 dynamicallychange relative to other smart nozzles 106 of the system.

FIG. 3 illustrates a detailed schematic view of an exemplary nozzlecontrol system 300. The control system 300 includes the master node 110communicatively coupled to one or more valves of the boom 104, such thatsystem pressure within the boom 104 can be controlled by the master node110. Further, the master node 110 includes inputs from one or more ofthe master flowmeter 202, the master pressure transducer 204, and themaster pulse width modulation (PWM) valve 206. Further, as describedherein, the master node 110 is coupled to the user interface 210 and, inan example, a battery 302, so as to provide power to one or more of themaster node 110 and user interface 210.

As shown in the embodiment of FIG. 3 , a smart nozzle 106 optionallyincludes an ECU 108 coupled to a valve 304 (e.g., a PWM valve, ballvalve, butterfly valve, or the like). That is, FIG. 3 illustrates 36ECUs relating directly to 36 nozzles of the nozzle control system 300,but embodiments are not so limited. The master node 110 iscommunicatively coupled, by nozzle CAN bus 208 to ECU-18 and ECU-19,wherein ECU-18 108 and ECU- 19 108 define a center region of the boom.From the center region of the boom, the ECUs 108 are communicativelycoupled to the most proximate ECU 108 in the direction toward eachterminal end 306 of the boom. That is, ECU-18 is communicatively coupleto ECU-17, which is communicatively coupled to ECU-16, and so forthuntil the optional terminator after ECU-1 is reached. The same patternholds for the other half of the boom. Although 36 ECUs 108 areillustrated, embodiments are not so limited.

Further, as shown in FIG. 3 , each ECU 108 is coupled to one PWM valve304, however, embodiments are not so limited. In another example, asingle ECU 108 is communicatively coupled to more than one PWM valve304. For instance, a single ECU 108 is communicatively coupled to morethan one valve, such as every other valve, arrays of valves alongportions of booms or the like. In an example, 12 ECUs split control ofthe 36 nozzles of the boom. In an example, a plurality of nozzles arepartitioned into nozzle groups, such that each nozzle group includes anECU 108 configured to control a nozzle group flow rate (or nozzlepressure that in turn controls flow) of the agricultural productdispensed from each nozzle of the nozzle group (by way of associatedcontrol valves) based on the nozzle characteristics, as describedherein, of the respective nozzles. Thus, a smart nozzle includes, but isnot limited to, a single nozzle, an associated valve and an associatedECU. In another example, a smart nozzle includes a group of nozzles(having associated valves) that are associated with a common ECU.

In still another example, the system 300 includes one or more locationfiducials associated with the system 300, the one or more locationfiducials are configured to mark the location of one or more nozzles (orECUs) of the plurality of nozzles on a field map (e.g., indexed withproduct flow rates, moisture content, crop type, agricultural producttype, or the like). Optionally, each of the nozzles, nozzle groups, orECUs 108 of the system is configured to control the agricultural productat individual rates according to the location of the one or more nozzles(or ECUs 108), the movement of the one or more nozzles relative to thefield, another frame of reference or the like (and optionally inaddition to the nozzle characteristics described herein). Further, eachof the plurality of nozzles (or ECUs 108) is optionally cycled, such ason/off, according to the location of the nozzle (or location of a nozzlegroup or ECU 108) relative to a frame of reference, such as a field.

In an example, each nozzle ECU 108 is programmable to receive, track, ormodify designated nozzle control factors (e.g., flow rate, the relatedspecified duty cycle, the actual duty cycle, or the like). For example,each ECU 108 monitors one or more of nozzle spacing, target flow ratefor the system or for the nozzle(s) controlled by the ECU, targetpressure for the system, speed of the agricultural sprayer, yaw rate,nozzle location on the field, or the like. Such examples provide thebenefit of comporting the system to user specifications, provide greaterprogrammability of the system, and providing cost effective nozzlespecific flow rate and pressure solutions (e.g., through modification ofvalve duty cycles). In yet another example, the ECUs 108 associated witheach nozzle are instead consolidated into one or more centralized nodesthat determine (e.g., monitor or calculate) one or more of actual flowrate, actual pressure or the like of each of the respective nozzles in asimilar manner to the previously described ECUs 108 associated with eachof the nozzles.

The controllers 116 (e.g., the ECU 108, the master node 110, or thelike) control the nozzle flow rate (or the timing of flow through thenozzle) based on a number of parameters, including, but not limited to:speed of the sprayer or boom, yaw rate, target system flow rate (e.g.volume/area), target system pressure, and on/off command at runtime.Such parameters permit the controllers 116 to calibrate the duty cyclecurve (e.g., by adjusting the actual duty cycle of a valve) of eachsmart nozzle needed to achieve one or more of the target nozzle flowrate, system target flow rate, system pressure, nozzle pressure, targetnozzle timing of each of the smart nozzles. For instance, calibratingthe duty cycle curve includes guiding an actual duty cycle of thenozzles (and their associated valves) to a specified duty cycle of thenozzles. The specified duty cycle corresponds to one or more of a targetflow rate, target pressure (combination of both) or the like. Each smartnozzle is further configured according to nozzle spacing on the boom,location on the boom, and nozzle type. Further, in some examples, eachsmart nozzle regulates or controls the nozzle flow rate (or pressure)based on the location of the nozzle in the field (as described above).

As described herein, the agricultural sprayer 100 (shown in FIG. 1 )includes a nozzle control system including a plurality of nozzles 106having one or more associated valves 304 (e.g., such as a PWM solenoidvalve as shown in FIG. 3 , or the like) that regulate flow in order toprovide a specified target application of an agricultural product fromthe nozzles 106. As a plurality of nozzles 106 are used across the boom104 (shown in FIG. 1 ), achieving specified flow performance for each ofthe nozzles 106 enhances application precision and accuracy whileminimizing application errors (e.g., misapplication, underapplication,overapplication, or the like). In some examples, one or more factorscause inconsistency in nozzle flow and droplet size (e.g., the size ofdroplets of agricultural product dispensed by the nozzle 106) of thesprayed agricultural product. Examples of these factors include, but arenot limited to voltage drop of a solenoid drive voltage due to chassiswiring resistance, manufacturing tolerances of the mechanical elementsin a valve itself (e.g., the valve 304, shown in FIG. 3 ), valve wear,valve contamination from the agricultural product, pressure variationsacross the boom or boom sections, variation due to an installed tip onthe outlet of the nozzle, or open-stroke and close-stroke transitiontimes for a moveable valve operator within the valve 304 controllingflow to the nozzle 106.

In an example, and as described in greater detail herein, a system forapplying an agricultural product (e.g., the sprayer 100, or the like)realizes specified operational flow performance out of a smart nozzle106 despite factors that negatively affect performance by determiningvariations between the specified performance and the actual performanceand instituting a correction (or corrections) at valves to achieve thespecified performance. For instance, the system controls a specifiedduty cycle of a valve versus an actual duty cycle of the valve 304 witha correction (discussed herein) that guides the actual duty cycle tocoincide with the specified duty cycle. In some examples the systemincludes a solenoid valve drive circuit and a solenoid valve monitoringcircuit. In another example, the system includes (or utilizes) analgorithm for tracking a position of a moveable valve operator (e.g., apoppet, or the like) of the valve 304 based on, for example, monitoringof back-emf (BEMF) generated in a solenoid coil by the moving valveoperator as it transitions between its open and closed positions in thevalve 304. In another example, monitoring (e.g., capturing, recording,observing, cataloging, compiling, collecting, or the like) of theperformance of the valve 304 optionally provides insight into valvehealth or nozzle faults and, for instance alerts a system user to aspecific problem (e.g., with the user interface 210, shown in FIG. 2 ).

FIG. 4 and FIG. 5 illustrate sectional views of an example of the valve304 in an open position and a closed position, respectively. The valve304 is optionally a solenoid valve, for instance an electro-mechanicaldevice that opens and closes an orifice by moving a moveable valveoperator 400 (e.g., a poppet, gate, or the like) in a valve body 402(e.g., a pressure vessel, frame, or the like). In an example, the valvebody 402 of the valve 304 contains a 1ug 404 (e.g., a ferromagneticmaterial) and a housing 406 (e.g., a non-ferromagnetic material) that isconnected to the lug 404. The valve operator 400 is movable in thehousing 406, for instance with a range of motion 407 to open and closethe valve. The valve operator 400 includes a seal 408 (e.g., a gasket,membrane or the like) coupled with a first end 410 of the valve operator400. In an example, movement of the valve operator 400 within thehousing 406 selectively opens and closes a channel 412 between a valveinlet 414 and a valve outlet 416. For example, the seal 408 engages witha valve seat 409 (shown in the closed configuration in FIG. 5 ) therebyinhibiting flow through the channel 412. In the open position, the seal408 is disengaged from the seat 409 (as shown in FIG. 4 ) therebyallowing flow through the channel 412 (e.g., because the valve operator400 is moved away from the seat 409). FIG. 4 includes arrows indicatingflow within the valve inlet 414 and the valve outlet 416.

In an example, the valve 304 is biased toward the closed position, forinstance with a biasing element 418, such as a coil spring, leaf spring,elastomer, magnet, or the like. The biasing element 418 optionallybiases the valve operator 400 toward the closed position. In an example,the moveable valve operator 400 includes an operator flange 401 and thehousing 406 includes a flare 411 The biasing element 418 (a spring inthis example) is coupled between the operator flange 401 and the flare411. In this example, the biasing element 418 provides a force betweenthe housing 406 and the valve operator 400 to bias the valve operator400 toward the closed position.

In some examples, the valve 304 operates by applying a voltage potentialto a coil 420 (e.g., a winding of wire, or the like) that generatescurrent in the coil 420. The coil 420 generates magnetic flux whencurrent flows through the coil 420. In an example, the moveable valveoperator 400 translates with respect to the coil 420 based on themagnetic flux generated by the coil 420. The current flowing through thecoil 420 optionally magnetizes the 1ug 404 (and the valve operator 400)of the valve 304. For instance, the lug 404 is ferromagnetic, and amagnetic pole is established that attracts (e.g., draws, pulls, pushes,drives, or the like) the valve operator 400 toward the 1ug 404.Accordingly, the valve 304 optionally includes a solenoid 421, and thesolenoid 421 includes (but is not limited to) the valve operator 400,the 1ug 404, and the coil 420.

The valve 304 optionally includes a magnetic flux frame 422 surroundingone or more of the lug 404 or the valve operator 400. The magnetic fluxframe 422 encapsulates the magnetic field between the lug 404 and valveoperator 400 and accordingly concentrates the magnetic field. Forinstance, the magnetic flux frame 422 enhances bounding of fluxgenerated by the coil 420 to concentrate the magnetic field between thelug 404 and the valve operator 400.

Referring again to FIG. 4 , as the amount of current flowing through thecoil 420 increases, the magnetic field generated by the coil 420increases as does the resulting force applied to the valve operator 400.For instance, an attractive force increases between the valve operator400 and the lug 404. As the attractive force generated (e.g., induced,developed, provided, or the like) by the magnetized lug 404 overcomesforces such as fluid pressure within the housing 406, bias from thebiasing element 418 or the like —-- the valve operator 400 begins movingfrom the closed position (FIG. 5 ) to the open position (FIG. 4 ). Asdescribed herein, the movement of the valve operator 400 is affected byone or more characteristics including the previously described fluidpressure, bias, or the like, and these characteristics alter themovement and accordingly vary an actual duty cycle of the valve 304 incomparison to a specified (e.g., desired) duty cycle.

A generated counter current (e.g., back electromotive force or back EMF)and corresponding magnetic field are examples of characteristics thatalter the performance of the valve 304 relative to a specified dutycycle. For example, as the valve operator 400 moves toward the openposition a counter current is generated in the coil 420 as the fluxlinkage changes because of a change of magnetically permeable materialwithin the magnetic field (e.g., more of the valve operator having ahigher magnetic permeability moves into the magnetic field and displacesfluid having a lower permeability). As the valve opens the flux linkageof the valve 304 changes due to the valve operator 400 occupying thepreviously fluid filled fluid gap 500. Conversely, when the valveoperator 400 is in the closed position (FIG. 4 ) the fluid gap 500 isfilled with the fluid having a lower magnetic permeability and the fluxlinkage again changes and generates counter current. The changes in fluxlinkage generate correspond counter currents (e.g., back EMF) thatresist otherwise specified operation of the valve including opening andclosing movements and thereby slow opening and slow closing as fluxlinkage changes and back EMF is generated.

The direction of the current generated in the coil 420 and its magneticfield caused by the moving valve operator 400 opposes the initialmagnetic field of the coil 420 (e.g., the magnetic field generated by acurrent flowing through the coil 420). In an example, opposition of theinitial magnetic field decreases the initial magnetic field generated bythe coil 420 (e.g., according to Lenz’s Law, or the like). Thus, in someexamples, as the valve operator 400 moves nearer the coil 420 (or withinthe housing 406), the magnitude of current in the coil is reduced tooppose the originally created field caused by the current applied to thecoil 420 (e.g., a ramping current, or the like).

FIG. 6 illustrates a schematic diagram of a nozzle control system 600.The agricultural sprayer 100 (shown in FIG. 1 ) includes the nozzlecontrol system 600. For instance, the nozzle control system 600 is usedin combination with one or more components (or functions) of the nozzlecontrol system 200 (shown in FIG. 2 ) or the nozzle control system 300(shown in FIG. 3 ). In an example, the nozzle control system 600includes the plurality of nozzles 106 (shown in FIG. 1 ) and one or moreassociated valves 304 (e.g., a PWM solenoid valve, or the like). Thevalves 304 (shown in FIG. 3 ) regulate flow to provide a specifiedtarget application rate of an agricultural product from the agriculturalsprayer 100.

The nozzle control system 600 includes one or more sensors 602 thatfacilitate monitoring of one or more electrical characteristics (e.g.,current, voltage, resistance, or the like) of components of the system600. For example, the nozzle control system 600 includes a coilcharacteristic sensor 604, for instance included in series with the coil420. In an example, the coil characteristic sensor 604 determines (e.g.,measures, monitors, obtains, provides, evaluates, observes, or the like)the magnitude of current through the coil 420 (or voltage across thecoil 420).

In an example, the system 600 includes a nozzle controller 606, and thenozzle controller 606 monitors the electrical characteristics of thesystem 600. For instance, the controller 606 is in communication withthe sensors 602, and the controller 606 monitors the sensors 602. Forexample, the controller 606 monitors the magnitude of the currentthrough the coil 420 (e.g., as determined by the characteristic sensor604). In some examples, the controller 606 performs one or moremathematical operations upon the monitored electrical characteristics.For instance, the controller 606 monitors one or more rates of change ofthe current through the coil 420.

As discussed herein, movement of the valve operator 400 facilitates flowthrough the valve 304. In an example, movement of the valve operator 400(e.g., with respect to the housing 406, shown in FIG. 4 ) generates achange in current through the coil 420. In some examples, the controller606 monitors the change in current through the coil 420 by way of thesensor 604. Accordingly, in this example the controller 606 determineswhen the valve operator 400 actually moves (in contrast to when itshould move based on a specified duty cycle) based on the monitoring ofelectrical characteristics with the sensor 604 (e.g., a decrease incurrent indicates movement of the valve operator 400). Thus, the controlsystem 600 (e.g., the controller 606 and sensor 604) detects actualmovement of the valve operator 400 including one or more of initial(e.g., beginning, starting, or the like) movement of the operator, fulltransition of the valve operator 400 (e.g., to open or closed positions)and movement therebetween.

The valve 304 is optionally closed (e.g., to inhibit flow in the channel412 between the valve inlet 414 and the valve outlet 416) by dissipatingthe magnetic field between the lug 404 and the valve operator 400. Forexample, the magnetic field between the lug 404 and the valve operator400 is dissipated and the biasing element 418 is thereby freed toovercome the attraction force between the valve operator 400 and the lug404. The valve operator 400 is biased with the biasing element 418toward the closed position. In an example, the current flowing throughthe coil 420 is reduced to dissipate the magnetic field generated by thecoil 420. For example, the voltage potential applied to the coil 420 isremoved from the coil 420. When the voltage potential is removed, thecurrent flowing through the coil 420 will decrease and the magneticfield generated by the coil 420 will also begin to dissipate (e.g.,decay, reduce, decrease, diminish or the like). When the magnetic fieldhas sufficiently dissipated, the biasing element 418 will bias the valveoperator 400 back towards the valve seat 409 and the closed position.

As the valve operator 400 begins to transition from the open position(shown in FIG. 4 ) toward the closed position (shown in FIG. 5 ), theamount of flux linkage in the magnetic circuit (e.g., between the lug404 and the valve operator 400) decreases. For instance, fluid having alower magnetic permeability fills the fluid gap 500 as the valveoperator 400 (with a relatively higher magnetic permeability) moves outof the gap and toward the closed position. A counter current isgenerated in the coil 420 as the valve operator 400 begins to move, andthe counter current opposes the change in flux linkage (e.g., accordingto Lenz’s law, or the like). The direction of the current generated inthe coil 420 by the transitioning valve operator 400 is such that thegenerated current generates a counter magnetic field opposed to thedissipating magnetic field in the coil 420. In an example, the generatedcurrent is monitored (e.g., by the controller 606 in communication withthe one or more sensors 602) to determine when the valve operator 400 istransitioning from the open position to the closed position.

In an example, the valve control system 600 includes a powerconditioning system 608. The power conditioning system 608 provides adrive voltage potential to operate the system 600 (including the valve304 having the coil 420). In some examples, the coil 420 acts like aninductor, and the current flowing through the coil 420 does not changeinstantaneously. The rate of adding energy into the coil 420 isoptionally increased, for example by increasing the drive voltagepotential (e.g., a voltage applied across the coil 420 with the powerconditioning system 608) to overcome the inductance of the coil 420.

In some examples, the open time for the valve 304 is improved byreducing the force of the biasing element 418 to make the biasing forceeasier to overcome. Increasing the rate that energy is dissipated fromthe coil 420 (and corresponding dissipation of the magnetic field)optionally reduces the close time of the valve 304 (e.g., a timeduration for the valve operator 400 to transition from the open positionto the closed position). Further, reducing the amount of energy to bedissipated from the valve 304 (e.g., the coil 420) optionally reducesthe close time of the valve 304. An increase in the spring constant ofthe biasing element 418 aids in returning the valve operator 400 to theclosed position (e.g., with the seal 408 engaged with the valve seat409) though it may conversely increase the duration of valve open as thestiffer biasing element 418 opposes opening.

In some examples, the coil 420 has a defined resistance, and when apotential is applied across the coil 420, a first amount of energy willbe dissipated by the coil 420 to build the magnetic field. A secondamount of energy is dissipated due to the resistance of the coil 420(e.g., as heat). Once the valve 304 transitions from the closed positionto the open position, the amount of magnetic field needed to maintainthe open position of the valve operator 400 is reduced because theinitial additional force to separate the seal 408 from the seat 409against the fluid pressure of the valve 304 is reduced (e.g., incomparison to when the valve operator is in the closed position). Withthe valve operator 400 in the open position, the fluid gap 500 (shown inFIG. 5 ) between the lug 404 and the valve operator 400 is removed(shown in FIG. 4 ). Since the field is optionally reduced, the amount ofcurrent running through the valve 304 is optionally reduced to maintainthe valve 304 (e.g., the valve operator 400) in the open position, forexample to save power (e.g., hitting and holding the valve operator 400in the open position). In an example, a full voltage potential isapplied to the coil 420 until the valve operator 400 transitions to theopen position from the closed position. Once the valve 304 has opened, areduced voltage potential (or current), or a modulated current (shown inFIG. 7 as the rapid saw tooth portion of the current plot), is appliedto the coil 420 to facilitate maintaining the valve operator 400 in theopen position while reducing the power consumption due to the wiringresistance in the coil 420.

In an example, the system 600 includes a coil drive voltage regulator610, for instance to facilitate operating the power conditioning system608 at a fixed, or nearly fixed voltage. The controller 606 optionallymodulates one or more of a high side switch 612 and a low side switch614, for instance to provide energy to the coil 420. The high sideswitch 612 and the low side switch 614 are optionally located on eitherside of the coil 420. For example, the high side switch 612 is includedin the system 600 on a first side of the coil 420. In an example, thelow side switch 614 is included in the system 600 on a second side ofthe coil 420. In an example, current flows through the coil 420 (andenergizes the coil 420) when the switches 612, 614 are closed. In someexamples, one or more of the switches 612, 614 are normally open, andmodulation of the switch closes a circuit and allows current to flowthrough the switches 612, 614. For instance, the switches 612, 614 arenormally open to facilitate conservation of power in the system 600(e.g., by selectively supplying power to the system 600 as needed).

In some examples, the system 600 includes one or more dissipationelements 616, for instance a first dissipation element 618 and a seconddissipation element 620. The dissipation elements 616 include (but arenot limited to) a flyback diode, freewheeling diode, clamp diode,transient voltage suppression diode, resistor, capacitor, or the like.In an example, the first dissipation element 618 includes a freewheelingdiode, and the dissipation element 618 facilitates recirculation ofcurrent through the coil 420 to facilitate the maintenance of themagnetic field with less energy. The dissipation element 616 optionallyhave a dissipation characteristic and dissipate energy within the system600, for instance from the coil 420. In some examples, the dissipationelement 616 helps recirculate energy within the system 600 (e.g., byrecirculating current through the freewheel path 632, or the like). Forexample, the dissipation element 618 facilitates recirculation ofcurrent through the coil 420 (with corresponding maintenance of themagnetic field) when the high side switch 612 is open (e.g., to inhibitcurrent flow through the switch 612) and the low side switch 614 isclosed (e.g., to allow recirculating current to flow between the switch614 and the dissipation element 616 with the intervening circuit havingthe coil 420 and ground).

The second dissipation element 620, for example, facilitatesdeenergizing of the coil 420. For instance, the dissipation element 620includes a clamping diode, and the dissipation element 620 quicklydissipates recirculating energy in the system 600 (e.g., removes,reduces, diminishes, dumps, minimizes or the like) from the coil 420 (orthe system 600) when both switches 612, 614 are opened. Accordingly,current flowing through the coil 420 is forced to divert to a flybackpath (e.g., the flyback path 634, or the like) for dissipation acrossthe dissipation element 620 (e.g., a clamping diode).

As described herein, the controller 606 monitors the sensors 602. Forinstance, the controller 606 determines when the valve operator 400moves based on the monitoring of electrical characteristics with thesensor 604 (e.g., a decrease in current corresponding to movement of thevalve operator 400 with respect to the housing 406). The system 600optionally includes a sense resistor 622. For instance, the senseresistor 622 facilitates monitoring of electrical characteristics of thesystem 600 (e.g., current through the coil 420), for example with thecontroller 606.

In an example, the controller 606 monitors the sensors 602 tocorrespondingly monitor the mechanical response of the valve operator400 (e.g., movement of the valve operator 400 between the closedposition and the open position). Monitoring of the mechanical responseof the valve operator 400 facilitates determining the actual duty cycleof the valve 304.

In some examples, the coil characteristic sensor 604 includes the senseresistor 622. For example, the sense resistor 622 facilitatesdetermining electrical characteristics of the coil 420. Monitoring ofthe electrical characteristics of the coil 420 facilitates monitoring ofmovement of the valve operator 400, for instance to determine when thevalve operator 400 begins to transition from the closed position to theopen position. In an example, the sense resistor 622 (in cooperationwith the controller 606) facilitates determining when the valve operator400 has fully transitioned to the open position (from the closedposition). In some examples, the sense resistor 622 is located in serieswith the coil 420. In an example, the sense resistor 622 is located inthe system 600 between the coil 420 and the switch 612. The senseresistor 622 is optionally located in series with the power conditioningsystem 608 and the coil 420. Thus, the coil characteristic sensor 604determines electrical characteristics of the coil 420 and facilitatesmonitoring of the electrical characteristic of the coil 420 with thecontroller 606. Accordingly, monitoring of the electricalcharacteristics of the coil 420 facilitates determining when the valveoperator 400 actually moves (e.g., because the mechanical response ofthe valve 304 differs from the electrical signals operating the valve304).

In an example, the sensors 602 include a dissipation characteristicsensor 624. For instance, the dissipation characteristic sensor 624determines one or more electrical characteristics of the dissipationelements 616. For example, the dissipation characteristic sensor 624determines a voltage across the second dissipation element 620, forinstance by determining a voltage at a dissipation voltage node 626between the coil 420 and the second dissipation element 620.

In an example, the dissipation characteristic sensor 624 facilitatesmonitoring of movement of the valve operator 400. For instance, thecontroller 606 optionally monitors the dissipation characteristic sensor624 to monitor the mechanical response of the valve operator 400 (e.g.,movement of the valve operator 400 between the open position and theclosed position). The controller 606 monitors the sensor 624 todetermine when the valve operator 400 begins to transition from the openposition to the closed position. In another example, the sense resistor622 (in cooperation with the controller 606) facilitates determiningwhen the valve operator 400 has fully transitioned to the closedposition (from the open position).

The system 600 optionally includes one or more signal processors 628.For instance, the signal processors 628 provide signal conditioning,amplification, or the like for components of the system 600. In anexample, the signal processors 628 facilitate monitoring of electricalcharacteristics by the controller 606. For example, the signalprocessors 628 condition electrical characteristics of the system 600for monitoring by the controller 606. For instance, the signalprocessors 628 allow the controller 606 to monitor the voltage at thedissipation voltage node 626. The signal processors 628 allow thecontroller 606 to monitor current flowing through the coil 420, forexample by monitoring the voltage across the sense resistor 622.

FIG. 7 illustrates a representation of one or more drive signals used toapply a specified duty cycle to a valve (e.g., the valve 304, shown inFIG. 3 ) and the resultant waveforms (e.g., one or more electricalcharacteristics, valve operator positions, specified and actual dutycycles, or the like) that are monitored (or determined) by thecontroller 606 in combination with the sensors described herein. FIG. 7shows one iteration (sequence) of an example specified duty cycle, theresulting actual duty cycle and the monitored or sensed characteristicsdescribed herein.

FIG. 6 shows arrows indicating flow of current through the system 600 inthe various configurations described herein (e.g., during energizing ofthe coil 420, maintenance of the energized coil, and dissipation ofenergy from the coil 420). The system 600 shown in FIG. 6 includes anenergizing path 630 (dot-dash stippled lines) that energies the coil 420to generate the magnetic field (e.g., to open the valve). In an example,current flows through the energizing path 630 when the high side switch612 and the low side switch 614 are closed. In another example, thesystem 600 includes the freewheel path 632 (dot-dash-dash stippledlines) that allows current to recirculate through the coil 420 (e.g., tomaintain the magnetic field and hold the valve operator 400 in the openposition). For instance, current flows in the freewheel path 632including ground and the coil 420 when the high side switch 612 is openand the low side switch 614 is closed. In yet another example, thesystem 600 includes a flyback path 634 (dot-dot-dash stippled lines)that dissipates energy from the coil 420. In an example, current flowsthrough the flyback path 634 when the high side switch 612 and the lowside switch 614 are open. Accordingly, the system 600 operates theswitches 612, 614 to direct current flow through one or more of theenergizing path 630, the freewheel path 632, or the flyback path 634 toaccomplish energizing of the coil 420 and generation of the magneticfield, maintenance of the magnetic field or dissipation of energy (andthe magnetic field), respectively.

FIG. 7 shows time intervals T0, T1, T1′, T2, T3, T4, T5, T6, T7, T8, andTC along a common X-axis for each of differing plots that followcharacteristics of the nozzle control system 600 during operation. The Yaxes of the respective plots are graduated by correspondingcharacteristics including, but not limited to, voltage, current, open orclosed states (and intermediate positions) or the like. In an example,the high side switch 612 and the low side switch 614 (shown in in theupper most plots of FIG. 6 ) are modulated between on off states. Thefirst (upper most) plot of FIG. 7 shows a low side switch state 700 andthe second plot shows a high side switch state 702. For instance, thehigh side switch state 702 is in the on state at T0, and the low sideswitch state 700 is in the off state at T4. In some examples, aspecified duty cycle 701 of the valve corresponds to the low side switchstate 700 having a corresponding specified time length 703, in thisexample of T0 to T4 of one full cycle (e.g., for a complete cycleincluding on and off of time T0 to TC). In other examples, the specifiedduty cycle 701 is represented as a percentage (e.g., 30, 40, 50, 60percent or so on) of one full cycle (time T0 to TC).

The controller 606 (in cooperation with the sensor 604, shown in FIG. 6) monitors a coil electrical characteristic 704 (e.g., current) of thecoil 420 as shown in the third plot of FIG. 7 . In another example, thecontroller 606 (in cooperation with the sensor 624, shown in FIG. 6 )monitors a dissipation element electrical characteristic 706 (e.g., oneor more of voltage, current, or the like) of the dissipation element 620shown in the fourth plot of FIG. 7 . Additionally, FIG. 7 shows a fifthplot of a valve operator position 708 indicating the position of thevalve operator 400 within the valve 304 with the bottom of the curvecorresponding to the closed position and the peak of the curvecorresponding to the open position. In an example, the actual duty cycleof the valve corresponds to the valve operator position 708.

Further, flow 709 agricultural product or the like through the valve ofthe valve system 600 is shown in the sixth plot (lower most) in FIG. 7and varies between a value of 0 (e.g., no flow) and 1 (e.g., 100 percentflow indicating the valve is open and steady state flow is provided). Asdiscussed herein, movement of the valve operator 400 permits (orinhibits) flow 709 through the valve.

As shown in FIG. 7 with the specified duty cycle 701 corresponding tothe low side switch state 700 and the actual duty cycle 713corresponding to the valve operator position 708 the valve operatormovement (opening and closing) lags in comparison to the specified dutycycle 701. For instance, the actual duty cycle 713 is clearly positionedbehind (time-wise) the specified duty cycle 701. This variation or lagbetween the actual and specified duty cycles 713, 701 causes errantapplication of agricultural product (e.g., quantity of product applied,location of application, or the like) relative to the specified dutycycle 701.

In one example, at time T0, the valve operator 400 is a closed positionas shown with the valve operator position plot 708. At time T0 both ofthe high side switch 612 and low side switch 614 (shown in FIG. 6 ) areclosed, a circuit is completed, and current begins to flow through thecurrent sense resistor 622 and the coil 420 (shown in FIG. 6 ). The coil420 initially behaves as an inductor (resisting the increased current),and the coil electrical characteristic 704 (e.g., current) does notchange instantaneously, but instead increases over time from T0 onward.For example, the coil electrical characteristic 704 increases with timeas shown in FIG. 7 after closure of the low side switch state 700 at T0.The resulting magnetic field generated from the coil 420 builds ascurrent increases. The building magnetic field applies a correspondingincreasing force to the moveable valve operator 400. As the magneticfield builds in the coil 420 and the lug 404 the force produced by thefield overcomes the combination of forces holding the valve operator 400in the closed position (e.g., pressure holding the valve 304 closed, thebias force holding the valve closed, and any other forces on the valveoperator 400 holding it closed position such as gravity) and theoperator 400 begins moving toward the open position.

The plotted coil electrical characteristic 704 shows a plurality ofinflection points 710. As previously described, as the valve operator400 begins to move (e.g., from closed to open) at approximately T1 acounter current is generated, and the counter current is graphicallyshown in FIG. 7 with a first inflection point 710A at T1 along the coilcharacteristic 704 plot. In another example, the valve operator 400 iscracked from the closed position and overcomes the pressure differentialbetween the upstream and downstream sides of the operator 400 — therebydecreasing the current for moving the operator. In contrast, if therewere no movement of the valve operator 400, the current would follow theupward trending path indicated by the first dashed line 712. In someexamples, monitoring of this electrical characteristic is utilized todiagnose a service issue with the valve 304, such as the absence of avalve operator 400 (e.g., after servicing). If the valve operator 400 ismissing from the valve 304 (e.g., errantly not replace after service)the electrical characteristic 704 will behave in a manner consistentwith first dashed line 712 and thereby facilitate diagnosis of a missingoperator 400.

The fifth plot of FIG. 7 shows the valve operator position 708, and thevalve operator position 708 corresponds to a position of the valveoperator 400 within the valve 304 with the bottom of the curvecorresponding to the closed position and the peak of the curvecorresponding to the open position. In an example, FIG. 7 shows thevalve operator 400 beginning to translate at time T1 (e.g., atranslation start time, corresponding to when the measured currentsignature starts to depart from the dashed line 712). In an example,Faraday’s law indicates that movement of the valve operator 400generates a field in the coil 420. Lenz’s law indicates that the currentgenerated by the valve operator 400 must oppose the direction of thebuilding magnetic field caused by the driver of the coil 420 (e.g., thecharacteristic 704, current, provided with the power conditioning system608, or the like). Accordingly, in an example, a change (e.g., decreasewith respect to time) in the coil electrical characteristic 704 (thethird plot), current, indicates one or more valve operator translationsignatures 714, specifically indicating when the valve operator 400begins opening movement (from closed) toward the lug 404 of the valve304.

In some examples, the controller 606 (shown in FIG. 6 ) compares themonitored electrical characteristics of the system 600 to the one ormore valve operator translation signatures 714 (shown in the third plotand the fourth plot of FIG. 7 ). For instance, a first valve operatortranslation signature 714A corresponds to at least one inflection point710 of the coil electric characteristic 704 for example at T1′. In anexample, the inflection points 710 include one or more of a change inmagnitude of a derivative of the characteristic 704, such as an increasein the rate that the slope is decreasing; a change in sign of the slopeof the characteristic 704; a change in sign of the derivative ofcharacteristic 704; peaks and valleys; or the like. The controller 606monitors the coil electric characteristic 704 (the third plot) andindexes at least a component of movement of the valve operator 400(shown in the fifth plot) based on features of one or more of the coilelectrical characteristic 704 or the dissipation element characteristic706 (the fourth plot). The controller 606 compares the indexed theelectrical characteristics to the valve operator translation signature714, for example by locating one or more of the inflection points in oneor more of the coil electric characteristic 704 or the dissipationelement characteristic 706.

Referring to FIG. 7 , as the valve operator 400 moves (indicated withthe valve operator position 708), the inductance of the coil 420 beginsto change as more of the volume inside the solenoid 421 is convertedfrom fluid with a low magnetic permeability to include the valveoperator 400 material with a relatively higher magnetic permeability.When the valve operator 400 reaches the top of the valve 304 (fullyopen, shown in FIG. 4 ) and shown at T2 in the fifth plot of FIG. 7 thevalve operator 400 stops moving and no longer generates a countercurrent in the coil 420. As shown with the coil electric characteristic704 (third plot), the current ceases decreasing at a second inflectionpoint 710B and begins to rise again. The current in the coil 420continues to build as it did before due to the potential through thecoil 420 (applied by the power conditioning system 608) without thecounter current provided by the previously moving valve operator 400.Accordingly, the second inflection point 710B corresponds to a secondvalve operator translation signature 714B indicating the valve operator400 is fully open. Thus, the controller 606 monitors the coil electriccharacteristic 704 and determines that the valve operator 400 has fullymoved to the open position based on the valve operator translationsignature 714B at time T2.

At time T2, the valve operator 400 is at the open position, and at timeT3 the controller 606 optionally reduces the current and associatedmagnetic field in the solenoid 421 for instance to save energy. Forinstance, the controller 606 maintains the current at a lower levelrecognized to retain (e.g., maintain) the valve operator 400 in the openposition. In an example, the current is modulated as shown with thesawtooth wave at T3 (e.g., with selective opening and closing of thehigh side switch 612 while the low side switch 614 is closed). Forexample, the electrical resistance in the coil 420 and loss in one ormore of the dissipation elements 616 and switches 612, 614 causes thecoil electrical characteristic 704 to decay. In order to maintain thefield generated by the coil 420, the high side switch 612 is modulatedto add energy to the solenoid 421 (e.g., the coil 420, or the like) asneeded to maintain the valve operator 400 open while minimizing powerusage.

The modulated current maintains the magnetic field in the solenoid 421with a slight imbalance (e.g., relative to gravity, fluid pressure, biasfrom the bias element or the like) to ensure retention of the valveoperator 400 in the open position. In an approach, the inductance of thecoil 420 is higher and the coil electrical characteristic 704 wouldfollow the path indicated by a second dotted line 716 in the coilelectrical characteristic 704 until it had saturated near a maximumvalue (e.g., approaches a limit, or the like) if the high side switch612 was maintained in the on state.

Modulating (e.g., selectively opening and closing) the high side switch612 circulates current in the system 600 at a level to generate amagnetic flux between the lug 404 and the valve operator 400 so as tomaintain the position of the valve operator 400 (e.g., in the openposition). Accordingly, the system 600 modulates the switch 612 toprovide a force imbalance incident upon the valve operator 400 andensure retention of the valve operator 400 in the open position whilereducing the power needed to maintain the position of the valve operator400.

In some examples, the high side switch 612 is modulated between the onstate and the off state (e.g., by selectively closing and opening theswitch 612) while maintaining the low side switch 614 in the on (e.g.,closed) state. Modulating the high side switch 612 while the low sideswitch 614 is in the on state causes current to flow through thefreewheel path 632 that, in some examples, includes the low side switch614, the first dissipation element 618, the sense resistor 622, and thecoil 420 (shown in FIG. 6 ). Accordingly, modulating the high sideswitch 614 reduces the power usage for the system 600 to maintain theposition of the valve operator 400 (e.g., in the open position). Thus,the performance of the system 600 is enhanced because of the reducedpower consumption to maintain the position of the valve operator 400. Insome examples, modulating the high side switch 612 between closed andopen (with the low side switch 614 closed) ensures retention of thevalve operator 400 in the open position is referred to as a hit-and-holdalgorithm.

In an example, during a rising edge of the low side switch control, ahit state is initiated in the high side switch 612 and the controller606 starts recording electrical characteristics, for example bymonitoring the current flowing through the coil 420. The controller 606analyzes the current data collected to determine if the valve operator400 has translated between the open position and the closed position. Insome examples, the controller 606 waits for a specified delay andrepeats the analysis if a translation is not detected.

In an example, when the controller 606 determines the valve operator 400has translated, the controller 606 optionally stops monitoring theelectrical characteristics of the coil 420 and maintains the position ofthe valve operator 400 (e.g., by modulating the switch 612, or thelike). Optionally, the controller 606 waits for a specified duration fora compare event in the low side switch 614 timer. When a compare eventoccurs, the low side switch 614 and the high side switches 612 areturned to an off state. Accordingly, current is forced to recirculate inthe flyback path 634 to be dissipated across the second dissipationelement 620 (e.g., a clamping diode, or the like). At this point, thecontroller 606 monitors the dissipation characteristic 706 (e.g., aflyback voltage, or the like). At the end of a wait period (e.g., either10 ms or the until the next update event), the controller 606 analyzesthe dissipation characteristic for transition signature 714.

The valve operator 400 is optionally moved to the closed position, forinstance at time T4. In an example, both the high side switch 612 andthe low side switch 614 are transitioned to the off state (e.g., toinhibit current flow through the switches 612, 614). With the switches612, 614 in the off state, current is inhibited from flowing through thefreewheel path 632. Accordingly, the current recirculating in the coil420 flows through the flyback path 634 (see FIG. 6 ), optionallyincluding the dissipation element 620 (e.g., a clamping diode), andbegins to dissipate to free the valve operator 400 to move to the closedposition.

FIG. 7 shows the monitored dissipation element electrical characteristic706 (e.g., one or more of voltage, current, or the like) of thedissipation element 620 in the fourth plot. In an example, thedissipation element electrical characteristic 706 (“dissipationcharacteristic 706”) includes a monitored voltage at the dissipationvoltage node 626 (shown in FIG. 6 ). Since the dissipationcharacteristic 706 is greater than the voltage potential across the coil420 with the switches 612, 614 in the off state, the energy of themagnetic field is quickly collapsed into a high electrical potential atthe dissipation voltage node 626. Conversely, as the voltage across thecoil 420 rapidly rises the coil characteristic 704 (e.g., current) shownin the fourth plot flowing through the coil 420 quickly collapses to 0,for instance as shown by time T5 proximate to time T4. As previouslydiscussed, current generates the magnetic field that retains the valveoperator 400 in the open position, and the rapid decrease of current(and corresponding magnetic field) accordingly permits the movement ofthe operator toward the closed position.

In between T5 and T6, the dissipation characteristic (voltage) 706 issaturated, current decreases as shown in the third plot, and themagnetic field generated by the coil 420 decreases quickly. As the fielddecreases, the corresponding force retaining the open position of valveoperator 400 against the fixed lug 404 dissipates – and the forceprovided by the biasing element 418 (shown in FIG. 4 ) overcomes theretaining force and closing movement of the valve operator 400 isinitiated. In some examples, the dissipation characteristic 706 includesone or more voltage inflection points 718. For instance, a first voltageinflection point 718A (shown at T5) correlates to the time when thecurrent is directed to the second dissipation element 620 (and thevoltage at the node 626 rises). In an example, a second voltageinflection point 718B (shown at T6) corresponds to when the dissipationelement 620 is no longer saturated. FIG. 7 shows the valve operatorposition 708 (fifth plot) begins movement from the open position to theclosed position at approximately T7 (e.g., a translation start time)corresponding to a third voltage inflection point 718C. Closing movementfinishes at approximately T8 (e.g., a translation stop time)corresponding to a fourth voltage inflection point 718D. In an example,as the valve operator 400 moves away from the collapsing magnetic field,the valve operator 400 induces a current in the coil 420, andaccordingly provides a corresponding change in the otherwise dissipatingvoltage of characteristic 706 having a third valve operator translationsignature 714C. For example, the valve operator translation signature714C includes a change (e.g., an increase with respect to time, or thelike) in the dissipation element electrical characteristic 706, voltagein the example shown. In an example, the third voltage inflection point718C corresponds to movement of the valve operator 400 (e.g.,translation signature 714C). Completion of movement corresponds to, forinstance, the fourth inflection point 718D and a fourth translationsignature 714D when the valve operator 400 comes to a rest (and thevalve 304 is closed).

In one example, Lenz’s law indicates that the current generated by thevalve operator 400 transitioning to the closed position opposes thechange in the characteristic 706 as a result of the collapsing magneticfield. Thus, in an example, instead of seeing the voltage decay of thecoil 420 (e.g., an inductor, or the like) that is discharging(represented by a third dotted line 720), the dissipation characteristic706 will rise and then fall relative to the previous decay until thevalve operator 400 has completed its movement (e.g., translation,transition, stroke, displacement, change, shift, or the like) from theopen position (e.g., at T7) to the closed position (e.g., at T8). In anexample where the field generated by the solenoid 421 is insufficient tomaintain the valve operator 400 in the open position, the valve operator400 will transition to the closed position prior to turning off theswitches 612, 614. At time T8, the valve operator 400 has fullycompleted movement to the closed position, and any remainder of thefield generated by the coil 420 decays based on the lower inductance inthe coil 420 since the fluid gap 500 has been reintroduced In someexamples, the valve 304 remains in this de-energized state until time TCwhich is the duration of a cycle.

Accordingly, the time duration between T1 (e.g., when the valve operator400 begins moving toward the open position) and T8 (e.g., when the valveoperator 400 moves to the closed position and the flow 709 through thevalve 304 stops) corresponds to an actual duty cycle 713 of the valve304. For example, the actual duty cycle 713 of the valve 304 correspondsto the time between actual opening of the valve operator 400 withbeginning of translation to the open position at T1 (in contrast to thepreceding operation of the switches 612, 614 at T0) and a translationstop time of the valve operator 400 at T8 (when the valve operator 400is in the closed position). As shown in FIG. 7 , the actual duty cycle713 is different than the specified duty cycle 701 corresponding to thelow side switch state 700. For instance, the actual duty cycle 713 lagsbehind the specified duty cycle 701 and its timing and correspondingcharacteristics such as length of time open or closed, initiation ofmovement, corresponding flow or the like varies relative to thespecified duty cycle 701.

As discussed herein, the system 600 guides the actual duty cycle 713 ofthe valve 304 to comport with the specified duty cycle 701. For example,the specified duty cycle 701 corresponds to the portion of the low sideswitch state 700 (e.g., from T0 to T4). The actual duty cycle 713corresponds to the valve operator position 708 shown in the fifth plotof FIG. 7 and determined from the coil electrical characteristic 704(e.g., current) in the third plot indicating the actual opening of thevalve and the dissipation element electrical characteristic 706 (e.g.,voltage) to the fourth plot indicating the actual closing of the valve.For instance, the actual duty cycle 713 corresponds to the valveoperator 400 in the open position (e.g., from T1 to T8). The system 600determines one or more errors (e.g., a difference, delta, or the like)between the specified duty cycle 701 and the actual duty cycle 713. Inan example, a portion of the error in the actual duty cycle 713 relativeto the specified duty cycle 701 is generated from differences in openingand closing movement of the valve operator 400 between the specified andactual cycles (e.g., lagging of opening and closing movement, variationin duty cycle length relative to the specified or the like).

The system 600 applies a correction, for example a magnetic fluxcorrection, to the specified duty cycle 701 to guide the actual dutycycle 713 of the valve 304 toward the specified duty cycle. In anexample, the correction applied to the specified duty cycle correspondsto the error determined between the actual duty cycle and the specifiedduty cycle. As one representative example, opening of the valve in theactual duty cycle 713 is delayed by 0.005 seconds (5 milliseconds or 5ms) relative to the specified duty cycle 701. The system modulates theswitches 612, 614 to advance the timing of the specified duty cycle by 5ms to guide the actual duty cycle 713 of the valve 304 to the specifiedduty cycle 701 (e.g., with a modified specified duty cycle). Thus, thesystem 600 adjusts (e.g., corrects, modulates or the like) the magneticflux generated by the coil 420 to achieve actual operation of the valveoperator 400 (opening, closing, and timing of the same) according to thespecified duty cycle. Accordingly, the system 600 minimizes errorbetween the specified duty cycle 701 and the actual duty cycle 713 toimprove the performance of the valve 304 (e.g., to open or close thevalve operator 400 at a desired point in time, permit flow through thevalve 304 for a specified period of time or the like).

FIG. 8 illustrates a diagram of duty cycle guidance, for instance tominimize error between the specified duty cycle 701 and the actual dutycycle 713 shown in FIG. 7 . In some examples, the duty cycle guidancediscussed herein is referred to as an algorithm 801. The controller 606generates a magnetic flux correction for an example specified duty cycle800 (FIG. 8 with an associated specified on period 802), an actual dutycycle 804 (with an associated actual on period 806) shown in the secondplot and an actual duty cycle 804′ (e.g., an updated actual duty cycle804 or valve performance) that is based on the specified duty cycle 800and a magnetic flux correction (collectively an applied duty cycle 808)is shown in the third plot of FIG. 8 . An example feedback control loop1100 for generating the applied duty cycle 808 is shown in FIG. 11 .

Referring first to FIG. 8 , the specified duty cycle 800 in the firstplot is shown with an associated specified on period 802 of 25milliseconds (“ms”) and conversely an off period of 25 ms for a totalcycle time of 50 ms. The specified duty cycle 800 is specified in someexamples as a percentage, and in this example corresponds to a 50percent duty cycle; the on period 802 is 50 percent of the full cycle of50 ms.

The actual duty cycle 804 (e.g., mechanical performance of the valve304) is shown in the second plot of FIG. 8 . As previously described,the movement of the valve operator 400 is detected, in one example asshown in FIG. 6 , to determine the actual duty cycle 713 in FIG. 7 andthe example actual duty cycle 804 in FIG. 8 . In the example shown inFIG. 8 , the actual duty cycle 804 extending between on and offtransitions 805, 807 of the valve operator is 22.3 ms. The error betweenthe length of the actual duty cycle 804 and the specified duty cycle 800is 2.7 ms. In another example, the actual duty cycle 804 is a 44.6percent duty cycle relative to the specified duty cycle of 50 percentshown in the upper plot of FIG. 8 (e.g., a negative 5.4 percent error).

The system 600 including for example the feedback control loop 1100 (ofFIG. 11 ) uses this error (e.g., 2.7 ms or 5.4 percent) to determine andapply a magnetic flux correction 810 (referred to as the duty cyclecorrection in FIG. 11 ) that modifies the signal for the specified dutycycle 800 to the applied duty cycle 808 to guide the mechanicalperformance of the valve 304 toward the specified duty cycle 800 (seethe third plot in FIG. 8 ) having performance (e.g., on time percentage,on duration or the like) corresponding to the original specified dutycycle 800. The fourth plot in FIG. 8 shows the third plot overlaid withthe second plot, thereby showing differences between the third plot(e.g., the actual duty cycle 804′) and the second plot (e.g., the actualduty cycle 804).

The magnetic flux correction 810 increases or decreases the flux in thevalve 304 to accordingly trigger a change in one or more of valve,opening or valve closing (e.g., opens, closes earlier, later, oneearlier one later, combinations of the same or the like) relative to theprevious actual duty cycle 804. The applied duty cycle 808 (based on thespecified duty cycle 800 with the magnetic flux correction 810), whenimplemented with the system 600, provides the actual duty cycle 804′shown in the third plot having a duration, percentage or the like), inthis example 25 ms, relative to the actual duty cycle 804 length of 22.3ms. The time length of the actual duty cycle 804′, 25 ms, corresponds tothe specified time length of 25 ms of the specified duty cycle 800. Theactual duty cycle 804′ is the actual valve performance of the valve 304driven with the specified duty cycle 800 and the magnetic fluxcorrection 810, and the actual duty cycle 804′ has a duration of 25 msthat matches the duration of the original specified duty cycle 800 shownin the upper plot of FIG. 8 . In other examples, if the actual dutycycle 804 is longer than the specified duty cycle 800, the system 600implements a magnetic flux correction 810 (e.g., a change in magneticflux that shortens the on performance of the valve) as part of theapplied duty cycle 808 to generate the actual duty cycle 804′ thatmatches the shorter specified duty cycle 800.

FIG. 8 shows the fourth plot, which includes the second plot overlaidwith the third plot. The monitoring of the actual performance of a valveand its associated valve operator to determine an actual duty cyclebased on detected valve operator movement (e.g., opening and closing ofthe valve operator) differences between the actual duty cycle 804 andthe specified duty cycle 800 are readily determined and corrected withsystem 600 described herein including implementation of the magneticflux correction 810. The system 600 drives the valve, with an appliedduty cycle 808 (the specified duty cycle including the magnetic fluxcorrection 810) that causes the valve to mechanically behave with anactual duty cycle 804′ that matches the specified duty cycle 800. Inother examples, the system 600 and the example feedback control loop1100 operate in an ongoing manner and accordingly modulate the specifiedduty cycle 800 with the magnetic flux correction 810 (collectively theapplied duty cycle 808) to vary operation of the valve 304. Forinstance, as an agricultural vehicle (e.g., a sprayer or the like)changes velocity, turns, increases or decreases flow rates in differentzones of a field or the like, the system 600 continues to monitor actualvalve performance (opening and closing of one or more valves) todetermine an actual duty cycle, compare the actual duty cycle with aspecified duty cycle, and adjust the performance of the valve with anapplied duty cycle based on the specified duty cycle modified with themagnetic flux correction 810 to achieve actual performance (e.g.,sprayer output, flow rate, a resulting actual duty cycle or the likecorresponding to the actual duty cycle 804′) that matches a specifiedduty cycle.

FIG. 9 illustrates an algorithm 900 for determining one or more actualduty cycles, for example a duty cycle corresponding to a time durationfor the valve operator 400 to transition between the closed position andthe open position (e.g., the open stroke transition times). Samples areoptionally collected during a first time interval (e.g., when themagnetic field is building in the solenoid 421), for example at 902. Inan example, an analog-to-digital-converter (“ADC”) with a direct memoryaccess controller (“DMA”) samples one or more electrical characteristicsof the system 600, such as at a fixed sample rate. In an example, at 904the electrical characteristic samples are analyzed, for instance withthe controller 606 looping through an index of the samples to locatepoints of interest (e.g., one or more of the valve operator translationsignatures 714). In another example, the controller 606 detects a value(e.g., one or more of the characteristics 704, 706) above a noisethreshold (e.g., a base noise margin), and the controller 606 optionallyrecords this as time T0. As the controller 606 continues analyzing thesamples, at 906 the controller 606 optionally records the first instanceof an inflection point (e.g., a peak, for instance the inflection point710A at T1′ in FIG. 7 ) that is greater than a first valve operatortransition threshold (e.g., a noise threshold, minimum value, floor, orthe like). In one example, T1′ corresponds to the inflection point 710Aand is, in some examples, more readily detected and T1′ is accordinglyinterpreted as equivalent to T1. In another example, at 908 thecontroller 606 records an instance of a second inflection point (e.g., avalley, for example the inflection point 710B at T2 in FIG. 7 ) with avalue that is greater than a second valve operator transition threshold.For instance, the second inflection point corresponds to the valveoperator 400 fully moving to the open position (shown with the valve,operator position 708 at T2 in FIG. 7 ).

The controller 606 optionally analyzes the samples (e.g., one or more ofan analog signal, a digital signal, or the like) to detect a second peakvalue that exceeds the second valve operator transition value. Forinstance, the valve operator 400 may bounce within the valve body 402,thereby causing multiple peak values above the minimum valve operatortransition value. Accordingly, at 910, the controller detects when theelectrical characteristics exceed a bounce threshold to determine whenthe valve operator 400 has moved to the open position (e.g., the valveoperator position 708 at T3, shown in FIG. 7 ).

The controller 606 determines when all values are defined at 914, suchas by detecting when the value of the electrical characteristics of thesystem 600 exceed one or more of the thresholds described herein (e.g.,a noise threshold, transition threshold, bounce threshold, or the like).At 916, when all values are defined, the controller 606 determines thatthe valve operator 400 did move (e.g., valve operator 400 is not stuck,bouncing, or the like) and proceeds to the hold state (e.g., byutilizing a hit-and-hold algorithm). If all values were not defined, at918 the controller 606 determines that a full transition of the valveoperator 400 did not occur and determines whether a wait duration hasexceeded a maximum transition time threshold, such as a thresholdcorrelating to the maximum hit duration of the hit-and-hold algorithm.In another example, the maximum transition time threshold correlateswith a point when the field in the coil 420 is nearly saturated. If thewait duration has not exceeded the maximum transition time threshold,the controller 606 returns to 904 and analyzes samples of the electricalcharacteristics of the system 600. If the wait duration exceeds themaximum transition time threshold, the controller 606 determines thatthe valve operator 400 has not transitioned (e.g., the valve operator400 is stuck or the operating pressure is too high) and the controller606 records that the valve operator 400 did not transition.

In an example, the controller 606 when the controller 606 records thatthe valve operator 400 did not transition, the controller 606 provides anotification that the valve operator 400 did not transition (e.g., bydisplaying a message on a user interface, or the like). For example, thecontroller 606 transmits a notification to a user interface (e.g., ascreen, dashboard, console, light emitting diode, pixel, or the like) toindicate to a user that the valve operator 400 did not transition. Inanother example, the notification provides the user with informationthat the duty cycle could not be implemented, for instance because thevalve operator 400 remained open (or closed) instead of transitioningaccording to the specified duty cycle. Failure to implement the dutycycle is indicative in some examples of poor valve health, for exampleover or under application of an agricultural product, plugging,inability by the valve to achieve the specified duty cycle. A failure toimplement the duty cycle triggers an implementation of a magnetic fluxcorrection in one example. If the correction is implemented andperformance is still out of line with the specified duty cycle a furtherindication is optionally provided of poor valve health.

FIG. 10 illustrates an algorithm 1000 for determining a translation ofthe valve operator 400 between the open position and the closed position(e.g., the close stroke transition times). In an example, at 1002 thecontroller 606 collects samples (e.g., data, information, electricalsignals, or the like) during the translation of the valve operator 400from the open position to the closed position. For instance, thecontroller 606 monitors a dissipation voltage node 626 during the closestroke. In an example, the controller 606 collects samples during aperiod of interest (e.g., when the magnetic field is decaying in thesolenoid 621).

At 1004, the controller 606 analyzes the samples collected duringtranslation of the valve operator 400. In some approaches, sampling themagnitudes of the sample values is unreliable at indicating valveoperator 400 transition times. In an example, the controller 606utilizes a derivative of the sample values (e.g., one or more electricalcharacteristics of the system 600, such as characteristics 704, 706) todetermine whether the valve operator 400 has transitioned. Thecontroller 606 optionally utilizes a stream derivative using, forinstance a 9-sample window. For example, the controller 606 uses theSavitzky-Golay stream derivative method to compare one or moreelectrical characteristics of the system 600 to one or more of the valveoperator translation signatures 714. In an example, as the streamderivative is calculated, the controller 606 analyzes the samples tolook for one or more of the inflection points 710, 718 or the like inthe electrical characteristics (or derivatives of the electricalcharacteristics) of the system 600. In another example, the valveoperator translation signature 714 corresponds to one or more of theinflection points 710 of the coil characteristic 704. In yet anotherexample, the valve operator translation signature 714 corresponds to oneor more of the inflection points 718 of the dissipation characteristic706. For instance, the inflection points 710, 718 include one or more ofa change in magnitude of a derivative of the characteristic 704 (or thecharacteristic 706), such as an increase in the rate that the slope isdecreasing; a change in sign of the slope of the characteristic 704 (orthe characteristic 706); a change in sign of the derivative ofcharacteristic 704 (or the characteristic 706); peaks and valleys;global maxima; global minima; local maxima; local minima; or the like.

In an example, at 1006 the controller 606 detects a first inflectionpoint (e.g., a peak, such as inflection point 718A) in the collectedsamples, and the first inflection point correlates to the time (e.g.,for the characteristic 706 at T5, shown in FIG. 7 ) when the current isdirected to the second dissipation element 620 (and the voltage at thenode 626 rises). At 1008, the controller 606 detects a second inflectionpoint (e.g., a change in slope, for instance the inflection point 718Bat T6 in FIG. 7 ), such as corresponding to a point when the seconddissipation element 620 is no longer saturated. For instance, the secondinflection point 718B is detected when the field decays below a clampedvalue of a clamp diode (e.g., for the characteristic 706 at T6, shown inFIG. 7 ). At 1010, the controller 606 detects a third inflection point(e.g., the inflection point 718C, shown in FIG. 7 at T7) indicating thepoint at which the valve operator 400 starts to transition to the closedposition. In another example, the algorithm 1000 includes, at 1012,detecting a fourth inflection point (e.g., the inflection point 718D,shown in FIG. 7 at T8) with the controller 606. The fourth inflectionpoint correlates to the point where the valve operator 400 has completedits transition to the closed position (indicated with the valve operatorposition 708 at T8 in FIG. 7 ). If all values are defined at 1014, at1016 the controller 606 determines that the valve operator 400 did move(e.g., valve operator 400 is not stuck, bouncing, or the like) andoptionally proceeds to the hold state. If all values were not recordedat 1014, at 1018 the controller 606 determines that a full transition ofthe valve operator 400 did not occur and optionally waits (e.g., for awaiting duration) before analyzing the electrical characteristics of thesystem 600 again. In some examples, the controller 606 determines that afull transition of the valve operator 400 did not occur and determineswhether a wait duration has exceeded a maximum transition timethreshold. The controller 606 optionally provides a notification whenthe wait duration exceeds the maximum transition time threshold.

FIG. 11 illustrates a duty cycle modulator 1100 for implementing amagnetic flux correction and implementing control of a valve accordingto a specified duty cycle 1102 and the magnetic flux correction (e.g.,an applied duty cycle). In some examples, the duty cycle modulator 1100is referred to as a feedback control loop 1100, algorithm or the like.In an example, at 1104 the controller 606 (see FIG. 6 ) provides thespecified duty cycle 1102 to a junction, such as a summation block 1106,and the output of the summation block 1106 is an applied duty cycle 1108(e.g., the applied duty cycle 808, shown in FIG. 8 ). As describedherein, in some examples, the duty cycle of the electrically controlledlow side switch 614 controls the valve 304 mechanics and how much fluidflows from the valve 304 (and is dispensed by the nozzle 106). In anexample, the specified duty cycle 701 (shown in FIG. 7 ) is associatedwith the actual duty cycle 713 of the valve 304. As described herein, insome approaches the actual duty cycle 713 does not match the specifiedduty cycle 701 (e.g., due to physical limitations in the construction ofthe valve 304). In an example, the system 600 corrects (includingminimizes) the variation or error between the specified duty cycle 1102and an actual duty cycle 1110 (e.g., as shown with the actual duty cycle804′), such as with the algorithm 1100.

For instance, when the system 600 decreases variations in the open timeof the valve 304 (between specified open and actual open), thecontroller 606 optionally increases the field generated by the coil 420.The increase in the generated field corresponds to an increase in powersupplied to the coil 420. In some examples, variations between dutycycles are mitigated by monitoring the feedback of the coilcharacteristic sensor 604 and dissipation characteristic sensor 624, forinstance to determine when the valve 304 actually transitions betweenthe open position and the closed position (e.g., when the valve 304actually strokes).

In an example, the controller 606 determines how the valve operator 400actually moved for a cycle of the valve 304. The controller 606compensates for variability in movement of the valve operator 400 (e.g.,a difference between specified duty cycle and actual duty cycle) with anapplied duty cycle 1108 that is based on the specified duty cycle with amagnetic flux correction, for instance corresponding to the differencebetween the specified and actual duty cycles. For example, at 1112, oneor more of the switches 612, 614 are modulated according to the appliedduty cycle 1108 (or specified duty cycle if no magnetic flux correctionis present) to thereby open and close the valve 304. The correspondingactual duty cycle 1110 is the output of the modulated switching at 1112.The algorithm 1100 at 1114 includes determining the (actual) valveoperator duty cycle. For example, the controller 606 monitors one ormore characteristics, such as the electrical characteristics 704, 106(that represent opening and closing of the valve), also referred toherein as the actual duty cycle 1110 (or the actual duty cycle 804 inFIG. 8 ).

In FIG. 11 , at 1116 the algorithm 1100 includes determining a dutycycle correction 1118 (corresponding to the magnetic flux correctionapplied to the valve 304). The duty cycle correction 1118 is implementedwith the specified duty cycle 1102 at the summation block 1106, therebygenerating the applied duty cycle 1108. The controller 606 uses theactual duty cycle determination (e.g., with the algorithm 1100 at 1114)to guide the actual duty cycle 1110 toward the specified duty cycle1102, thereby minimizing error between the specified duty cycle 1102 andthe actual duty cycle 1110 (and minimizing associated differencesrelative to a specified flow rate, pressure of the agricultural productat the valve, droplet size, spray pattern or the like). In an example,factors that cause variability from valve to valve do not changedramatically from cycle to cycle for those respective valves. In someexamples, the controller 606 utilizes a magnetic flux correction (e.g.,a duty cycle correction) to compensate the specified duty cycle 1102 ofone or more valves 304 to improve the performance of the system 600 forapplying an agricultural product. Accordingly, the variability of valveperformance from a specified duty cycle and corresponding specifiedperformance (e.g., flow rate, pressure or the like) or performancebetween the valves 304 can be compensated for, for instance by guidingthe actual duty cycles 1110 of the valves 304 toward the specified dutycycle 1102.

For instance, at 1112, system feedback is conditioned into the dutycycle correction 1118 (e.g., an error offset, or the like) and used tomodulate the low side switch 614 with the applied duty cycle 1108 thatdiffers from the specified duty cycle 1102 to guide the actual dutycycle 1110 of the valve 304 to the specified duty cycle 1102.Accordingly, the system tightly controls the output of the valve 304(e.g., flow of an agricultural product, or the like) based on a desiredtarget output (e.g., valve flow rate, agricultural product volume or thelike).

As described herein, at 1116, the controller 606 implementing thealgorithm 1100 determines the duty cycle correction 1118 (e.g., aduration, percentage or the like that represents the magnetic fluxcorrection) based on error (e.g., differences) between the specifiedduty cycle 1102 and the actual duty cycle 1110. The duty cyclecorrection 1118, when implemented at the coil 420 of the valve 304corresponds to the magnetic flux correction. The duty cycle correction1118 is combined with the specified duty cycle 1102 at the summationblock 1104 to accordingly generate the applied duty cycle 1110.Accordingly, the duty cycle correction 1118 is applied to the specifiedduty cycle 1102 to generate the applied duty cycle 1108 that guides thevalve performance (e.g., the actual duty cycle 804′ described herein andshown in FIG. 8 ) to the original specified duty cycle 1102 (e.g., asprovided at 1104). For instance, an ‘on’ duration (e.g., open period ofthe valve during a cycle of operation) for the actual duty cycle 804′corresponds with the ‘on’ duration of the specified duty cycle 1102 whenthe applied duty cycle 1108 includes the duty cycle correction 1118(e.g., the magnetic flux correction).

As described herein, the controller 606 monitors feedback such aselectrical characteristics that correspond to mechanical performance ofthe valve 304 as the valve operator transitions (e.g., between with anopen stroke or a close stroke). The controller 606 optionally compilesone or more metrics related to valve health or valve performancerelative to other valves in the system (e.g., to notify a user thatperformance of one or more of the valves is degraded, for instance belowa performance threshold). In another example, the controller 606compiles a health metric based on the correction, such as the magneticflux correction or duty cycle correction 1118 (in FIG. 11 ), thatadjusts valve performance toward the specified duty cycle 701.Optionally, the health metric is graduated according to the magnitude ofthe duty cycle correction 1118. For instance, as the duty cyclecorrection 1118 increases, the health metric conversely decreases (e.g.,indicating the valve is less able to perform as specified and instead isdriven with progressively greater correction).

For example, a magnitude of the duty cycle correction (e.g., determinedwith the algorithm 1100, shown in FIG. 11 ) is indicative of the healthof the valve 304 (e.g., whether the valve 304 is operating as intended).In an example, the controller 606 determines that the valve 304 isperforming as intended if the duty cycle correction 1118 is within 10percent of the specified duty cycle 1102 (e.g., the duty cyclecorrection 1118 is within 0.010 ms for a specified duty cycle 1102 of0.100 ms). Thus, when the duty cycle correction 1118 is within 10percent of the specified duty cycle 1102, the controller 606 optionallyprovides a notification that the valve 304 is at maximum health. Forinstance, the controller 606 may provide a notification that a healthvalue of the valve 304 is at 100 health points out of 100 total healthpoints.

In another example, when the duty cycle correction 1118 exceeds 10percent of the specified duty cycle (e.g., a duty cycle correctionexceeding 0.010 ms for a duty cycle time of 0.100 ms), the controller606 provides a notification that the health value of the valve 304 isdecreasing. For example, the health value of the valve decreases below100 total health points if the duty cycle correction 1118 exceeds 10percent of the specified duty cycle 1102. The health value of the valve304 optionally decreases in a graduated manner (e.g., linearly,exponentially, logarithmically, or the like) as the duty cyclecorrection 1118 increases above 10 percent of the specified duty cycle1102. For example, the controller 606 provides a notification that thevalve 304 has 50 health points (out of 100 total health points) when theduty cycle correction 1118 exceeds 15 percent of the specified dutycycle 1102 (e.g., the duty cycle correction exceeding 0.015 ms for aduty cycle time of 0.100 ms ms). In another example, the controller 606provides a notification that the valve 304 has 0 health points (out of100 total health points) when the duty cycle correction 1118 exceeds 20percent of the specified duty cycle 1108 (e.g., the duty cyclecorrection exceeding 0.020 ms for a duty cycle time of 0.100 ms). Insome examples, the controller 606 provides a notification that the valve304 needs service, for instance when the duty cycle correction 1118exceeds 25 percent of the specified duty cycle 1102 (e.g., the dutycycle correction exceeding 0.025 ms for a duty cycle time of 0.100 ms).Accordingly, the controller 606 utilizes the duty cycle correction 1118to assess the health of the valve 304 and notify a user regarding thehealth of the valve (e.g., by displaying a health value including healthpoints of the valve, or the system 600, with a user interface).

In some examples, pressure changes quickly at the valve outlet 416 oncethe seal is broken (on the open stroke) or sealed (on the close stroke).As the valves low output depends on the pressure at the outlet, thesystem provides a specified output when the system utilizes the subjectmatter described herein. For instance, the error offset metric ishelpful for determining valve health between valves. The system providesoperation conditions as similar as possible between valves of thesystem, and in some examples the system compares how much offset a givenvalve has and determines if the system is out of specifications (e.g.,outlet restrictions in the case of blocked tip detection).

In some approaches a sprayer for applying an agricultural product cancause skips, or areas in application coverage that do not get touched bydispensed agrochemical, for instance if the driven duty cycle of anozzle is less than 50%. In practice, this number is 50% because nozzletips are generally selected to overlap 50% with their neighboring nozzleand nozzles are run out of phase with one another. Many things affectthe skip area like machine speed, yaw rate, application height, mixingin the air due to boom or machine turbulence or local wind conditions.The total area of the skip depends on one or more things, the effectivevelocity at the nozzle, the application width of the tip, and the offtime of the nozzle when operating at less than 50% duty cycle.

The area can be calculated using the following formula:

Skip Area = (Nozzle Width * Effective Nozzle Velocity * (1 - (dutycycle/100)) / frequency [for duty cycles < 50%]

In practice, we currently recommend keeping our valve (“NCV”) minimumduty cycle at or around 25% to minimize areas where skips may occur.However, the NCV can physically perform well at much lower duty cyclesas the limitation in the NCV is how quickly the valve operator 400 cantransition from the closed to open states or opened to close states. Forinstance, at 40PSI, the NCV can open in about 7ms and close in about 5ms. At a frequency of 10 Hz this correlates to a minimum on-time dutycycle of about 5% and at 20 Hz, this correlates to a minimum on-timeduty cycle of 10%. In general, if the frequency was increased near theminimum duty cycle range to 20 Hz it would cause the skip distance todecrease and increase out, confidence at lowering the NCV minimum dutycycle threshold. In the industry, the trend is to increase the baseoperational frequency at all duty cycles in order to minimize skip areaor distance. However, increasing the frequency causes more stress on thephysical mechanics of the NCV (like the valve operator 400 and seals),and in return, lowering the frequency would lengthen the lifespan of theNCV. Increasing the frequency also causes more transitions from the opento closed and closed to open states during which the pressure in thevalve varies and can cause non-linear flow or pressure drops which canaffect control and target droplet size.

Therefore, being able to dynamically adjust the operational frequency ofthe NCV at different duty cycles and effective velocities to target aminimum skip area would be ideal for targeting an optimal life time,minimalizing inconsistencies in droplet size from the tip, or minimizingtime in non-linear flow rate application periods.

Technically, the frequency at any duty cycle above 50% could be reducedto the lowest allowable frequency that still produced an acceptablecoverage pattern (e.g., acceptably sized double-coverage areas). Oneapproach to implement dynamic frequency adjustment can be that thefrequency is fixed at set duty cycles and then would use a percentthreshold to switch between the frequencies. This approach has thedisadvantage of the fact that it doesn’t use the effective nozzlevelocity to minimize the skip distance, which may make it unnecessarilyrun at higher frequencies when it doesn’t need to do so to acceptablyminimize skip coverage areas.

Another way would be to have the user select a maximum skip distance andthen based off that setting, each NCV could use its effective speed andoff time to determine its effective skip distance and make a decision toincrease or decrease the frequency to control the skip distance belowthe maximum entered value.

It is also worth noting that because nozzles typically run out of phasewith their neighbors, frequency steps would have to happen in powers oftwo to ensure that nozzles could still be synced locally to one anotherand remain out of phase.

FIG. 12 illustrates a block diagram of an example machine 1200 (e.g.,the controller 606, or the like) upon which any one or more of thetechniques (e.g., methodologies) discussed herein may perform, forexample one or more of the algorithms 801, 900, 1000, or 1100. Examples,as described herein, may include, or may operate by, logic or a numberof components, or mechanisms in the machine 1200. Circuitry (e.g.,processing circuitry) is a collection of circuits implemented intangible entities of the machine 1200 that include hardware (e.g.,simple circuits, gates, logic, etc.). Circuitry membership may beflexible over time. Circuitries include members that may, alone or incombination, perform specified operations when operating. In an example,hardware of the circuitry may be immutably designed to carry out aspecific operation (e.g., hardwired). In an example, the hardware of thecircuitry may include variably connected physical components (e.g.,execution units, transistors, simple circuits, etc.) including a machinereadable medium physically modified (e.g., magnetically, electrically,moveable placement of invariant massed particles, etc.) to encodeinstructions of the specific operation. In connecting the physicalcomponents, the underlying electrical properties of a hardwareconstituent are changed, for example, from an insulator to a conductoror vice versa. The instructions enable embedded hardware (e.g., theexecution units or a loading mechanism) to create members of thecircuitry in hardware via the variable connections to carry out portionsof the specific operation when in operation. Accordingly, in an example,the machine readable medium elements are part of the circuitry or arecommunicatively coupled to the other components of the circuitry whenthe device is operating. In an example, any of the physical componentsmay be used in more than one member of more than one circuitry. Forexample, under operation, execution units may be used in a first circuitof a first circuitry at one point in time and reused by a second circuitin the first circuitry, or by a third circuit in a second circuitry at adifferent time. Additional examples of these components with respect tothe machine 1200 follow.

In alternative embodiments, the machine 1200 may operate as a standalonedevice or may be connected (e.g., networked) to other machines. In anetworked deployment, the machine 1200 may operate in the capacity of aserver machine, a client machine, or both in server-client networkenvironments. In an example, the machine 1200 may act as a peer machinein peer-to-peer (P2P) (or other distributed) network environment. Themachine 1200 may be a personal computer (PC), a tablet PC, a set-top box(STB), a personal digital assistant (PDA), a mobile telephone, a webappliance, a network router, switch or bridge, or any machine capable ofexecuting instructions (sequential or otherwise) that specify actions tobe taken by that machine. Further, while only a single machine isillustrated, the term “machine” shall also be taken to include anycollection of machines that individually or jointly execute a set (ormultiple sets) of instructions to perform any one or more of themethodologies discussed herein, such as cloud computing, software as aservice (SaaS), other computer cluster configurations.

The machine (e.g., computer system) 1200 may include a hardwareprocessor 1202 (e.g., a central processing unit (CPU), a graphicsprocessing unit (GPU), a hardware processor core, or any combinationthereof), a main memory 1204, a static memory (e.g., memory or storagefor firmware, microcode, a basic-input-output (BIOS), unified extensiblefirmware interface (UEFI), etc.) 1206, and mass storage 1208 (e.g., harddrive, tape drive, flash storage, or other block devices) some or all ofwhich may communicate with each other via an interlink (e.g., bus) 1230.The machine 1200 may further include a display unit 1210, analphanumeric input device 1212 (e.g., a keyboard), and a user interface(UI) navigation device 1214 (e.g., a mouse). In an example, the displayunit 1210, input device 1212 and UI navigation device 1214 may be atouch screen display. The machine 1200 may additionally include astorage device (e.g., drive unit) 1208, a signal generation device 1218(e.g., a speaker), a network interface device 1220, and one or moresensors 1216, such as a global positioning system (GPS) sensor, compass,accelerometer, or other sensor. The machine 1200 may include an outputcontroller 1228, such as a serial (e.g., universal serial bus (USB),parallel, or other wired or wireless (e.g., infrared (IR), near fieldcommunication (NFC), etc.) connection to communicate or control one ormore peripheral devices (e.g., a printer, card reader, etc.).

Registers of the processor 1202, the main memory 1204, the static memory1206, or the mass storage 1208 may be, or include, a machine readablemedium 1222 on which is stored one or more sets of data structures orinstructions 1224 (e.g., software) embodying or utilized by any one ormore of the techniques or functions described herein. The instructions1224 may also reside, completely or at least partially, within any ofregisters of the processor 1202, the main memory 1204, the static memory1206, or the mass storage 1208 during execution thereof by the machine1200. In an example, one or any combination of the hardware processor1202, the main memory 1204, the static memory 1206, or the mass storage1208 may constitute the machine readable media 1222. While the machinereadable medium 1222 is illustrated as a single medium, the term“machine readable medium” may include a single medium or multiple media(e.g., a centralized or distributed database, and/or associated cachesand servers) configured to store the one or more instructions 1224.

The term “machine readable medium” may include any medium that iscapable of storing, encoding, or carrying instructions for execution bythe machine 1200 and that cause the machine 1200 to perform any one ormore of the techniques of the present disclosure, or that is capable ofstoring, encoding or carrying data structures used by or associated withsuch instructions. Non-limiting machine readable medium examples mayinclude solid-state memories, optical media, magnetic media, and signals(e.g., radio frequency signals, other photon based signals, soundsignals, etc.). In an example, a non-transitory machine readable mediumcomprises a machine readable medium with a plurality of particles havinginvariant (e.g., rest) mass, and thus are compositions of matter.Accordingly, non-transitory machine-readable media are machine readablemedia that do not include transitory propagating signals. Specificexamples of non-transitory machine readable media may include:non-volatile memory, such as semiconductor memory devices (e.g.,Electrically Programmable Read-Only Memory (EPROM), ElectricallyErasable Programmable Read-Only Memory (EEPItOM)) and flash memorydevices; magnetic disks, such as internal hard disks and removabledisks, magneto-optical disks; and CD-ROM and DVD-ROM disks.

The instructions 1224 may be further transmitted or received over acommunications network 1226 using a transmission medium via the networkinterface device 1220 utilizing any one of a number of transferprotocols (e.g., frame relay, internet protocol (IP), transmissioncontrol protocol (TCP), user datagram protocol (UDP), hypertext transferprotocol (HTTP), etc.). Example communication networks may include alocal area network (LAN), a wide area network (WAN), a packet datanetwork (e.g., the Internet), mobile telephone networks (e.g., cellularnetworks), Plain Old Telephone (POTS) networks, and wireless datanetworks (e.g., Institute of Electrical and Electronics Engineers (IEEE)802.11 family of standards known as Wi-Fi®, IEEE 802.16 family ofstandards known as WiMax®), IEEE 802.15.4 family of standards,peer-to-peer (P2P) networks, among others. In an example, the networkinterface device 1220 may include one or more physical jacks (e.g.,Ethernet, coaxial, or phone jacks) or one or more antennas to connect tothe communications network 1226. In an example, the network interfacedevice 1220 may include a plurality of antennas to wirelesslycommunicate using at least one of single-input multiple-output (SIMO),multiple-input multiple-output (MIMO), or multiple-input single-output(MISO) techniques. The term “transmission medium” shall be taken toinclude any intangible medium that is capable of storing, encoding orcarrying instructions for execution by the machine 1200, and includesdigital or analog communications signals or other intangible medium tofacilitate communication of such software. A transmission medium is amachine readable medium.

FIG. 13 illustrates a schematic diagram of an example of a system 1300for modulating one or more of the valves 304. For example, the system1300 includes the controller 1302 (in one example the master node 110shown in FIGS. 2, 3 ). In some examples, the controller 1302 includesthe controller 606 (or the controller 606 is a component of the nozzlecontrol systems 600A-C described herein). For instance, the controller1302 includes processing circuitry that facilitates operation of thesystem 1300 (and the valves 304). In an example, the agriculturalsprayer 100 (shown in FIG. 1 ) includes one or more controllers, forinstance one or more of the controller 1302 or the controller 606 (shownin FIG. 6 ). In another example, the nozzle control system 200 (shown inFIG. 2 ) includes the controllers (e.g., controller 1302, controller606, or the like). In yet another example, the control system 300 (shownin FIG. 3 ) includes the controllers e.g., (controller 1302, controller606, or the like).

In an example, the controller 1302 is in communication with one or moreof the nozzle control systems 600 (e.g., components of the smart nozzles106, associated ECUs or the like). For instance, the system 1300includes a first nozzle control system 600A, a second nozzle controlsystem 600B, and a third nozzle control system 600C. The first system600A includes a first valve 304A having a first coil 420A. The secondsystem 600B includes a second valve 304B having a second coil 420B. Thethird system 600C includes a third valve 304C having a third coil 420C.

In one example, the controller 1302 modulates the valves 304 accordingto one or more duty cycles, such as specified duty cycles modifiedaccording to one or more of valve operator errors, pressure errors orthe like. For example, the controller 1302 is in communication with thefirst system 600A and energizes the coil 420A, for instance according toa first specified duty cycle and a first magnetic flux correction (e.g.,duty cycle corrections corresponding to valve operator error, pressureerror or the like). The controller 1302 is in communication with thesecond system 600B and energizes the coil 420B, for instance accordingto a second specified duty cycle and a second magnetic flux correction.The controller 1302 is in communication with the third system 600C andenergizes the coil 420C, for instance according to a third specifiedduty cycle and a third magnetic flux correction. Accordingly, thecontroller 1302 operates the valves 304. In another example, thecontroller 1302 provides an initial flow rate (or specified duty cycle)to each of the systems 600A-C, and the systems 600A-C having, respectiveECUs independently determine applied duty cycles based on the initialflow rate or corresponding specified duty cycle and the errors discussedherein (e.g., valve operator duty cycle errors, pressure errors or thelike). Optionally, the initial specified duty cycle or specified flowrate is provided to each of the systems having the associated valves304A-C, and the corresponding systems 600A-C determine the differingapplied duty cycles for the associated valves 304A-C and coils 420A-C.In another example, the systems 600A-C and associated controllers 606 ofthe valves 304 (e.g., ECUs of smart valves) determine the specified dutycycle values from specified flow rates received from the controller 1302(or the master node 110).

In some examples, the controller 1302 facilitates modulation of one ormore of the valves 304 out of phase with each other, for instance toconserve power usage by the system 1300. For example, the first valve304A is modulated out of phase with the second valve 304B. The firstvalve 304A is modulated out of phase with the third valve 304C.Accordingly, the first valve 304A is modulated out of phase with one ormore of the second valve 304B or the third valve 304C. In anotherexample, the second valve 304B is operated in phase with the third valve304C. The first valve 304A is modulated out of phase with the secondvalve 304B and the third valve 304C (with the valves 304B, 304Cmodulated in phase with each other). Accordingly, modulation of thevalves 304 out of phase with each other reduces the number of valves 304that are drawing power simultaneously within the system 1300.

In an example, the controller 1302 modulates the first valve 304A out ofphase with the second valve 304B at a specified phase. The controller1302 operates the valve 304A, for example by operating a moveable valveoperator (e.g., valve operator 400, shown in FIG. 4 ) with the coil420A. The controller 1302 optionally determines an actual phase of thevalve 304, such as by determining the actual duty cycles of the valves304 and determining the actual phase between the actual duty cycles ofthe valves 304. The controller 1302 operates the valve 304A according tothe specified duty cycle and a magnetic flux correction (e.g., anapplied duty cycle) to guide the actual phase of the valve 304A towardthe specified phase. For instance, the controller 1302 determines anerror between the specified phase and the actual phase of the valves304. The controller 1302 implements a correction to the modulation ofthe valves 304, for example to reduce (or minimize) error between thespecified phase and the actual phase of the valves 304.

In some examples, a plumbing system of a sprayer has a pressure dropalong the boom that varies from nozzle location to nozzle location thatdepends on the amount of flow going to each nozzle location. Thisvariable pressure drop can cause issues, for example with our pressurecontrol algorithm. In some approaches, the algorithm assumes that thepressure at each nozzle is the same as the pressure measured at thecenter of the boom. The variable pressure drop can also affect dropletsize across the boom as the pressure at each nozzle location, forinstance because the droplet size is dependent on nozzle pressure. Toovercome controlling the flow incorrectly in the presence of thispressure drop, a controller integrates the system efficiency, but thisadds latency to the control mechanism and can affect how much variationin flow rate or droplet size occurs between locations on the boom.

The pressure drop at each location can be found through modeling knownaspects of the machine configuration like the diameter(s) of theplumbing, length of the plumbing to each nozzle, types of tubing, typesof restrictions or fittings along the boom, target flow rate at everynozzle location along the boom, and some characteristics about the typeof liquid being dispensed. The system can experimentally validatepressure drop values on a configuration by running the system at a knownflow rates at each nozzle and then measure the associated pressure dropsalong the boom. By modeling or characterizing the system, the system(e.g., a controller) can compensate the pressure at each nozzle to anaverage target pressure by controlling to an overall slightly higherpressure at the center of the machine. This pressure offset can stillcause an issue with the inside nozzles having a higher than targetpressure and dispensing more liquid and the outside nozzles having alower than target pressure and dispensing slightly less liquid. Theeffective pressure could be calculated at each nozzle or valve, and thenas discussed herein the system can compensate the flow rate by adjustingthe duty cycle of the valves or nozzles to match their target flow rateeven in the presence of the nominal pressure drop at their location.

FIG. 14 shows another example of a sprayer 1400. The previous systems,such as the system 1300; controller 1302 (master node 110); controllers606 associated with nozzle control systems 600, such as the ECUsdiscussed herein; or the like are configured for use with the sprayer1400. As further discussed herein, a sprayer control system, referred toas a duty cycle modulator 1500, is shown in FIG. 15 and is configuredfor use with the sprayer 1400. The duty cycle modulator 1500 is similarin at least some aspects to the duty cycle modulator 1100 shown in FIG.11 . In the present example the duty cycle modulator 1500 is configuredto determine one or more of operator duty cycle error or pressure errorand compensate the determined errors with modulated control of the valveduty cycle.

The sprayer 1400 shown in FIG. 14 includes a consolidated system havingthe product injection reservoir 1406 and the injection pump 1408 feedinginto an injection port 1410 of a header 1412 of the sprayer 1400. Forinstance, the carrier fluid is pumped from a carrier reservoir 1402 by acarrier pump 1404 and supplemented with the injection product at theinjection port 1410 (e.g., by the injection pump 1408). One or both ofthe carrier pump 1404 or the injection pump 1408 are operated as systempressure regulators, for instance to control the system pressure (PS).As discussed herein, control of the system pressure (PS or PS′) isconducted to minimize pressure error as an optional component of dutycycle modulation.

As further shown in FIG. 14 , a mixer is provided downstream from theinjection port 1410 for mixing the injection product with the carrierfluid prior to delivery through the header 1412 to the boom tubes 1420,the boom sections 1428 and the spray nozzles 1424.

As shown in FIG. 14 , the injection product is provided to the flow ofcarrier fluid upstream from the spray nozzles 1424 and the boom sections1426 (each examples of product dispensers). In other examples, theinjection product is provided in a localized manner, for instance with aparallel set of injection plumbing (having its own header, injectionboom tubes or the like) to the header 1412 and boom tubes 1420 for thecarrier fluid. In this example, the injection pump 1408 communicates theinjection product under pressure to the control valves 1422, and thecontrol valves 1422 include one or more components, such as injectionvalves, configured to selectively inject the injection product to thecarrier fluid proximate to the product dispensers, such as the boomsections 1426 having multiple spray nozzles 1424, or in anotherconfiguration to spray nozzles 1424 associated with the control valves1422 in a one to one basis. The injection control valves precede orproceed the control valves 1422, for instance with unidirectional valvesto prevent back flow.

The control valves 1422 of the smart nozzles (e.g., having ECUs and oneor more of the spray nozzles 1424) are provided along the boom tubes1420. The control valves receive flow rate instructions from the masternode (also referred to as a main controller) 110 and implement the flowrate instructions as a corresponding specified duty cycle. As discussedherein, the specified duty cycle is, in various examples, modified withthe example duty cycle modulators 1100, 1500 (1500 is shown in FIG. 15 )based on performance and characteristics associated with the respectivecontrol valves 1422 or proximate to the control valves 1422 (e.g., localpressure and corresponding pressure error relative to a systempressure). Example valve performance and characteristics associated withcontrol valves 1422 include, but are not limited to, variations inactual duty cycle (e.g., movement of the valve operator) relative to thespecified duty cycle, or pressure errors (e.g., pressure variance)proximate to the control valves 1422 relative to a system pressure thatcause flow rate, droplet or spray pattern deviations through the spraynozzles 1424.

In the example shown in FIG. 14 , pressure errors (also referred to aspressure variances) are shown proximate to associated control valves1422. As previously discussed one or more of the carrier pump 1404,injection pump 1408 or other device, such as a pressure regulatingvalve, act as pressure regulators for the sprayer 1400 (e.g., sprayersystem). The pressure regulator provides the agricultural product (e.g.,mixed carrier fluid and injection product, carrier fluid for downstreammixing with injection product or the like) at a system pressure (PS orPS′). In one example, shown with the first pressure plot providedbeneath the right boom tube 1420 the system pressure (PS) is initiallylocalized along the header 1412. Because of fluid mechaniccharacteristics of the boom tube 1420, fittings, the control valves orthe like the system pressure gradually decreases along the boom tube1420, for instance as shown at each of P1, P2, P3 and P4 in the firstplot. As pressure decreases along the boom tube 1420, flow rate throughthe associated control valves 1422 and spray nozzles 1424correspondingly decreases. Pressure errors, PE1, PE2, PE3, PE4 areillustrated in the first pressure plot based on the difference betweensystem pressure (PS) and the associated pressures (P1-P4) and representthe potential degradation of pressure along the boom tube 1420 andindicate the degradation of sprayer output for product dispensers, suchas spray nozzles 1424 along the boom tube 1420.

In one variation, the sprayer control system including one or more of acontroller 1302 (e.g., the master node 110) or the like discussed hereinoperates the system pressure regulator (or regulators) at pressuresabove a specified system pressure, for instance a system overpressure(PO). As shown in the second pressure plot in FIG. 14 , the systemoverpressure (PO) is provided proximate to the header 1412, for instanceat interior ends of the boom tubes 1420. In one example, the systemoverpressure generally minimizes pressure errors along the boom tube1420. For instance, a displaced specified system pressure (PS′) isprovided along the boom tube 1420, in this example at a relativelycentral location. PS’ provides the specified system pressure at alocation along the boom tube 1420 that minimizes pressure error at theextremities of the boom tube 1420. For instance, in the example shownP4′ has less error (PE4′) than the specified system pressure shown inthe second plot as PS′. Conversely, P1′ includes pressure error (PE1′)corresponding to an elevated pressure due to the system overpressure(PO). The pressure error PE1′ has an opposed sign to PE4′ because P1′ isgreater than PS′. The control valves 1422 associated with P1′ and PE1′will have an increased flow rate relative to a specified flow raterelated to the valve 1422 from the main controller (such as the masternode 110). As described further herein, duty cycle modulation based onpressure error (e.g., PE1-PE4 or PE1′-PE4′) is implemented to correctflow rate deviation caused by the variation in pressure.

FIG. 14 includes a series of pressure monitors 1430A-D proximate to oneor more of the control valves 1422. In one example, the pressuremonitors 1430A-D correspond to pressure transducers installed along oneor more of the boom tube 1420, proximate to the control valves 1422,proximate to the associated spray nozzles 1424 or the like. Optionally,multiple monitors are installed proximate to the control valves 1422 andthe spray nozzles 1424 associated with the control valves 1422.

In other examples, the pressure monitors 1430A-D include othercomponents, analysis of the operation of components, known systembehavior based on previous benchmark testing, performance registries orthe like that facilitate the determination of pressure errors. In oneexample, one or smaller number of pressure monitors 1430 are providedalong the boom tube 1420 and an incrementor/decrementor is implementedto step up (or step down) the measured pressure at a first location toapproximate pressures at other locations along the boom tube. Forinstance, through experimentation, fluid mechanic calculations or thelike a relationship between system pressure, flow rate, tube dimensionsand other components is determined. The incrementor/decrementor isconfigured to implement the relationship and according step up or stepdown pressure at locations spaced from an initial benchmark locationsuch as the system pressure (PS) proximate to the header 1412 or the PS′location provided along the boom tube 1420. Similarly, a stock system insome examples has known performance characteristics including knownpressure measurements (or pressure drops) along the boom tube 1420 inrelation to various system pressures and flow rates. The performancecharacteristics are retained in a system performance register, andpressures (P1, P1′, or the like) and corresponding pressure errors (PE1,PE1′) are determined through indexing flow rate and system pressurerelative to a corresponding location of the sprayer 1400 plumbing, suchas a location (e.g., of a control valve 1422) along the boom tube 1420relative to the header 1412 or system pressure regulator.

In another example, the pressure monitor includes a flow rate topressure transformer configured to determine pressure proximate to oneor more of the control valves 1422 according to flow rate through theone or more spray nozzles 1424 associated with the valve 1422 or throughthe valve 1422 itself. By measuring the flow rate the pressure (andpressure drop across the valve 1422) is readily determined and comparedagainst the system pressure to determine the local pressure error.

In still another example, performance of the control valve 1422, such asthe valve operator 400 (see FIGS. 4, 5 ), is analyzed to determinepressure proximate to the valve 1422. As previously discussed and shownin FIG. 7 the control valve 1422 (e.g., its movement when driven) isanalyzed to assess valve performance. For instance, the coil currentplot in FIG. 7 provides various indications of valve operator 400movement. The inflection point 710A for current indicates the valveoperator 400 has begun movement and accordingly ‘cracked’ the sealbetween the operator 400 and valve seat 409. The fluid pressure (e.g.,P1, P1′ or the like) on the upstream side of the operator 400 relativeto the pressure on the downstream side (atmospheric generally (ATM), or0 psi) along with the spring force of the spring 418 is overcome and theoperator 400 begins to move. The current proximate to the inflectionpoint 710A scales with the pressure differential (delta P) between theupstream and downstream sides of the control valve 1422 (e.g., the valveoperator 1400). For instance, as the delta P increases (e.g., with ahigher system pressure, such as at P1 or proximate to the known systempressure, PS) the current correspondingly rises as additional current isapplied to overcome the higher delta P. Conversely, as the delta Pdecreases, for instance at P4 in FIG. 14 , along the boom tube 1420relative to atmospheric pressure the current correspondingly decreases.With analysis of valve performance at different pressure differentialsand indexing of the pressure differentials to corresponding currentmeasurements the plot at FIG. 7 is, in one example, used to determinethe delta P at a control valve. Because delta P is generally determinedrelative to atmospheric pressure (ATM in FIG. 14 ) on the downstreamside of the control valve 1422 the pressure at the upstream side (e.g.,along the boom tube 1420 and proximate to the valve 1422) is determined.For instance, a delta P for the left most valve of the right boom tube1420 based on electrical current is 57 psi in an example and isequivalent to 57 psi on the upstream side of the control valve 1422(e.g., P1 or P1′) assuming 0 psi (ATM) on the downstream side of thevalve 1422. Further, by knowing the system pressure (PS, PS′) thepressure error, PE, PE′, for the control valve 1422 is readilydetermined (PS - P1 or PS′ - P1′), and then used as an input for dutycycle modulations (e.g., as shown in FIG. 15 ).

FIG. 15 is a schematic of an example duty cycle modulator 1500configured to control (e.g., maintain, modify, guide or the like) theduty cycle of one or more control valves 1422 according to determinederrors, for instance with one or more of operator duty cycle error,pressure error or the like (e.g., one or more characteristics of thesystem or valve that deviate from specified values). As previouslydiscussed with the duty cycle modulator 1100, the duty cycle correctionsdiscussed are in one example, implemented as magnetic flux correctionsthat change the specified duty cycle (e.g., corresponding to a specifiedflow rate) to provide the specified flow rate, spray pattern, dropletsize or the like through analysis and response to determined errors inthe system or valve.

In some examples, the duty cycle modulator 1500 is referred to as afeedback control loop 1500, algorithm or the like and is included with acontroller 606 of a smart nozzle (ECU or systems 600A-C in FIG. 13 ). Inan example, at 1504 the controller 606 (see FIG. 6 ) optionally receivesa specified flow rate (e.g., from the controller 1302, master node 110or the like) and provides a corresponding specified duty cycle 1502 to ajunction, such as a summation block 1506. The output of the summationblock 1506 is an applied duty cycle 1508 At 1512, the applied duty cycleis implements, for instance, with one or more of the low side and highside switches 614, 612 and the controller 606 shown in FIG. 6 .

The duty cycle modulator 1500 shown in FIG. 15 includes a firstcharacteristic error loop. In this example, the first loop correspondsto valve performance of the control valve 1422 (or 304) including, butnot limited to, variation of actual duty cycle relative to the specifiedduty cycle. At 1514 the actual duty cycle of the control valve 1422 isdetermined. The comparator 1516 compares the actual duty cycle with thespecified duty cycle and determines the valve operator duty cycle errorbased on the difference. As previously discussed, the valve operatorduty cycle error is one example of a duty cycle correction 1518 providedto the summation block 1506 for generation of the applied duty cycle1508.

As further shown in FIG. 15 , the duty cycle modulator 1500 includesanother characteristic error loop in communication with the remainder ofthe modulator 1500 to compensate for a different variation or error. Inthis example, the duty cycle modulator 1500 compensates for pressurevariation or error proximate to one or more control valves 1422 (or 304)relative to a system pressure, such as PS or PS′ in FIG. 14 . Pressureerror, such as deviation from system pressure, PS, at a control valve1422 correspondingly decreases flow rate (if a negative error), and inin the present example is compensated with a duty cycle correction thatchanges (e.g., increases if a negative error) the specified duty cycleto provide additional flow from control valve 1422 experiencing thepressure error.

At 1520, a pressure monitor (e.g., pressure transducer, knowncharacteristics of the sprayer 1400, registry, electrical characteristiccorresponding to pressure or the like) determines the pressure proximateto the control valve 1422. A comparator 1522 compares the determinedpressure (e.g., P1-P4, P1′-P4′) relative to the system pressure (PS,PS′) to determine the pressure error (PE1-PE4, PE1′-PE4′) proximate tothe control valve 1422.

In the example shown in FIG. 15 , a pressure error to duty cycletransformer is provided that converts the determined pressure error to aduty cycle correction. One example of relationship between pressureerror and a corresponding duty cycle correction is shown below.

$DC_{corr} = DC_{targ}\left( \frac{\sqrt{\frac{PS}{SG}} - \sqrt{\frac{PS - PE}{SG}}}{\sqrt{\frac{PS - PE}{SG}}} \right)$

In the example correction, DC_(corr) is the duty cycle correction (e.g.,for modification of the specified duty cycle to the actual duty cycle);DC_(targ) is the specified duty cycle (e.g., based on flow rate, systempressure or the like, for instance provided by the master node 110 orcontroller 1320); PS is the current system pressure (PS, PS’, forinstance relative to atmosphere) sent from the main controller to thecontrol valve, and PE is the difference between system pressure (PS, PS’or the like) and the pressure proximate to the control valve 1422 (P1,P1′ or the like); and SG is the specific gravity of the liquidagricultural product.

The duty cycle correction (DC_(corr)) is the duty cycle correction 1518provided to the summation block 1506 of the duty cycle modulator toaccount for pressure error at the associated control valve 1422.Implementing the duty cycle correction provides an actual duty cycle1508 for implementation (e.g., at 1512, for instance with the switches612, 614) to compensate for the determined error and its effects(decreased flow rate, inaccurate spray pattern, droplet size or the likebecause of the pressure error) In an example, this modulation isprovided for one or more (or each) of the control valves 1422 to provideindependent corrections for each of the control valves 1422 according tothe characteristics of the system (and the valve) proximate to eachvalve 1422. Optionally, the duty cycle correction based on thedetermined pressure error is provided by itself to the summation block1506 for the duty cycle modulator 1500 (and the associated controller)to determine the actual duty cycle. In another example, the duty cyclecorrection is applied in combination with other duty cycle corrections,such as the valve operator duty cycle error (and correspondingcorrection) show at 1516 in FIG. 15 . In still other examples,additional duty cycle corrections are determined based on one or more ofsystem (sprayer 1400) errors valve errors or the like to provide valve1422 and spray nozzle 1424 performance closely approximating theperformance specified, for instance based on the original specified dutycycle for the control valve 1422 (e.g., based on a specified flow rate).

In another example, for instance with the second pressure plot shown inFIG. 14 (having P1′, PE1′ and so on) the pressure error at the first andsecond control valves 1422 (e.g., corresponding to the pressure monitors1430A, B) is optionally a different sign of pressure error. Forinstance, P1′ (and P2′) are greater than PS′, and the corresponding PE1′(and PE2′) indicate higher pressures at the associated valves 1422 thanPS′. In this case, the pressure errors determined at 1522 and theassociated pressure based duty cycle correction determined at thetransformer 1524 are a subtractive duty cycle correction, and the actualduty cycle corresponds to the specified duty cycle 1502 decreased by thepressure based duty cycle correction.

FIG. 16 is a block diagram illustrating one example of a method 1600 forcontrolling one or more spray nozzles, for instance through duty cyclecompensation for system and valve errors as discussed herein. Indescribing the method 1600 reference is made to one or more components,features, functions or the like described herein. Where convenientreference is made to the components or features with reference numerals.Reference numerals provided are exemplary and are not exclusive. Forinstance, the features, components, functions or the like described inthe method 1600 include but are not limited to the correspondingnumbered elements, other corresponding features described herein, bothnumbered and unnumbered as well as their equivalents.

At 1602 a liquid agricultural product (e.g., carrier fluid, mixture ofcarrier fluid and injected product, or injection product) is supplied toat least one control valve 1422 at a specified system pressure. Forinstance, the liquid agricultural product is regulated (e.g., pumped orrestricted) at a specified initial pressure (PS, PS‘ or overpressure,PO, that provides PS′). At 1604, the at least on the control valve 1422is driven at a specified duty cycle. For instance, an ECU (e.g.,controller 606) of a smart nozzle receives a specified flow rate, andthe ECU translates the specified flow rate to a corresponding specifiedduty cycle, and the valve operator of the control valve 1422 is drivenaccording to the specified duty cycle, for instance to provide thespecified flow rate of the liquid agricultural product through one ormore associated spray nozzles 1424.

At 1606, performance of the at least one control valve 1422 is monitoredincluding one or more characteristics of the valve itself and the systemproximate to the valve. For instance, in one example, at 1608 a valvepressure is determined proximate to the at least one control valve 1422.The valve pressure proximate to the valve 1422 is determine with one ormore features including measuring valve pressure proximate to the valve(e.g., with a pressure transducer). In another example, the valvepressure is determined with assignment of a valve pressure valueaccording to incrementing or decrementing of the system pressure basedon a location of the at least one control valve, for instance withempirical or experimental behavior of the sprayer system 1400.Optionally, the valve pressure is determined with assignment of a valvepressure valve taken from a system performance register having pressurevalues for the at least one control valve according to the location ofthe at least one control valve (e.g., along the boom tube 1420, relativeto a system pressure regulator, relative to an indexed system pressureor the like). In still another example, the valve pressure is determinedby generating a valve pressure value based on the flow rate of theliquid agricultural product through the at least one control valve(e.g., with the flow rate, dimensions of the valve or spray nozzle, thevalve pressure is mathematically or empirically determines). In yetanother example, the valve pressure is determined by generating a valvepressure value based on valve operator performance. As discussed herein,the performance of the valve is monitored and pressure proximate to thecontrol valve 1422 is determined from the performance. For instance,applied current to open the valve from the closed position is associatedwith corresponding pressure differences across the control valve (e.g.,pressure differences or delta between atmospheric on the downstream sideand the upstream side of the valve). The pressure difference, in oneexample, corresponds to the pressure proximate to the control valve(e.g., P1 or P1′ in FIG. 14 ) and is compared with the initial systempressure (PS, PS‘) to determine the pressure error (PE, PE‘).

At 1610, driving of the at least one control valve 1422 is modulatedaccording to the monitored valve performance. As discussed herein, oneor more errors are determined (e.g., detected, calculated, generated,assigned or the like) for valve performance or system characteristicsproximate to the valve, and the specified duty cycle for the controlvalve 1422 is modified to compensate for the determined errors. At 1612,the determined valve pressure is compared with a specified systempressure (e.g., PS, PS′ in FIG. 14 ) to determine a pressure error, suchas PE1 or PE1′ (or pressure errors associated with the other valves1422) in FIG. 14 . At 1614 an applied duty cycle is generated based onthe specified duty cycle (e.g., corresponding to a specified flow ratefor the valve 1422 or its associated spray nozzle(s) 1424) modified bythe pressure error. In one example, the pressure error is transformed toa duty cycle and added or subtracted from the specified duty cycle(e.g., at the summation block 1506 in FIG. 15 ). At 1616, the method1600 includes driving the at least one control valve 1422 at the appliedduty cycle. Operating the at least one control valve 1422 with theapplied duty cycle compensates one or more of flow rate through thevalve and its associated spray nozzle(s), spray nozzle spray pattern ordroplet size or the like for the determined error (e.g., pressure error,valve operator duty cycle error, alone or in combination, or the like).

Several options for the method 1600 follow. In one example, generatingthe valve pressure value based on valve operator performance includesgenerating the valve pressure value based on one or more of movement ofthe valve operator or electrical characteristics associated withmovement of the valve operator.

In another example, monitoring the valve performance of the at least onecontrol valve includes determining an actual valve operator duty cycleof the at least one control valve. Optionally, modulating driving of theleast one control valve includes comparing the actual valve operatorduty cycle with the specified duty cycle to determine a valve operatoryduty cycle error. In this example, generating the applied duty cycleincludes generating the applied duty cycle based on the specified dutycycle modified by the pressure error and the valve operator duty cycleerror. The pressure error includes a pressure based duty cyclecorrection, the valve operator duty cycle error includes a valveoperator based duty cycle correction. Generating the applied duty cycleincludes generating the applied duty cycle based on the specified dutycycle modified by the pressure based duty cycle correction and the valveoperator based duty cycle correction, for instance as shown in FIG. 15with the summation block 1506.

The method 1600 optionally includes spraying the liquid agriculturalproduct from a spray nozzle (e.g., nozzle 1424 or an array of spraynozzles 1424 as part of a boom section 1426, see FIG. 14 ) incommunication with the at least one control valve 1422 driven at theapplied duty cycle.

In another example, the at least one control valve 1422 includes aplurality of control valves 1422, and driving the at least one controlvalve 1422 at the specified duty cycle is conducted for each of thecontrol valves 1422. Monitoring valve performance and modulating drivingof the at least one control valve are conducted for each of the controlvalves 1422, for instance, to provide independently determinedcorrections and compensated operation for each of the valves. In anotherexample, monitoring valve performance and modulating driving of each ofthe control valves 1422 is conducted independently for each of thecontrol valves based on valve pressure proximate to each control valve1422, respectively.

Optionally, the (initial) specified duty cycle varies for each of thecontrol valves 1422, for instance because of boom location, boomrotation, field indexing of flow rate for nozzles/valves withinspecified zones or the like. Similarly, the corrections and compensatedoperation of the control valves 1422 is based on the varied specifiedduty cycles for each of the respective control valves 1422.

In another example, supplying the liquid agricultural product to the atleast one control valve 1422 at the specified system pressure includessupplying the liquid agricultural product at an elevated system pressure(e.g., PO as shown in FIG. 14 ) greater than the specified systempressure (PS‘). Supplying the liquid agricultural product includesproviding the liquid agricultural product at the specified systempressure PS′ along at least one location of a sprayer boom having the atleast one control valve 1422 and a boom tube 1420 interconnecting the atleast one control valve and a source of the liquid agricultural product.Optionally, the at least one control valve 1422 includes a plurality ofcontrol valves 1422 distributed along the boom tube 1420. Supplying theliquid agricultural product to the plurality of control valves at thespecified system pressure includes supplying the liquid agriculturalproduct at an elevated system pressure (PO) greater than the specifiedsystem pressure (PS′), and providing the liquid agricultural product atthe specified system pressure (PS′) along a sprayer boom having the boomtube 1420. As discussed herein, the elevated system pressure (PO) andassociated system pressure (PS‘) minimize the pressure error (e.g.,PE1′, PE2′ and so on) at one or more of the control valves 1422 of theplurality of control valves according to supply of the liquidagricultural product at the elevated system pressure.

VARIOUS NOTES & ASPECTS

Aspect 1 can include subject matter such as a sprayer control system,comprising: a plurality of smart nozzles, each of the smart nozzlesincludes: at least one control valve having a valve operator; anelectronic control unit (ECU) configured to operate the valve operator;and one or more spray nozzles, wherein the at least one control valveand the ECU are configured to control a flow rate of liquid agriculturalproduct through the one or more spray nozzles; and a duty cyclemodulator in communication with the ECU and configured to generate anapplied duty cycle of the at least one control valve, the duty cyclemodulator includes: a specified duty cycle input having a specified dutycycle; a valve monitor configured to determine an actual valve operatorduty cycle of the at least one control valve; a valve operatorcomparator configured to compare the actual valve operator duty cyclewith the specified duty cycle and generate a valve operator duty cycleerror; a pressure monitor associated with the at least one control valveconfigured to determine a valve pressure proximate to the at least onecontrol valve; a pressure comparator configured to compare the valvepressure with a system pressure and generate a pressure error; and anapplied duty cycle generator configured to generate the applied dutycycle based on the specified duty cycle modified by the valve operatorduty cycle error and the pressure error.

Aspect 2 can include, or can optionally be combined with the subjectmatter of Aspect 1, to optionally include wherein the valve monitorincludes a valve operator monitor configured to monitor movement of thevalve operator or electrical characteristics associated with movement ofthe valve operator to determine the actual valve operator duty cycle.

Aspect 3 can include, or can optionally be combined with the subjectmatter of one or any combination of Aspects 1 or 2 to optionally includewherein the pressure monitor includes one or more of: a pressuretransducer proximate to the at least one control valve; anincrementor/decrementor configured to assign pressure values accordingto location of the at least one control valve; a system performanceregister having pressure according to location of the at least onecontrol valve; a flow rate to pressure transformer configured todetermine the valve pressure based on the flow rate through the one ormore spray nozzles; or an operator performance to pressure transformerconfigured to determine the valve pressure based on valve operatorperformance.

Aspect 4 can include, or can optionally be combined with the subjectmatter of one or any combination of Aspects 1-3 to optionally includewherein valve operator performance includes one or more of movement ofthe valve operator or electrical characteristics associated withmovement of the valve operator.

Aspect 5 can include, or can optionally be combined with the subjectmatter of one or any combination of Aspects 1-4 to optionally includewherein the ECU includes the pressure monitor and the valve monitor, andthe ECU is configured to monitor one or more of electricalcharacteristics or movement of the valve operator to determine theactual valve operator duty cycle and the valve pressure proximate to theassociated at least one control valve.

Aspect 6 can include, or can optionally be combined with the subjectmatter of Aspects 1-5 to optionally include wherein the duty cyclemodulator includes a pressure error to duty cycle transformer configuredto determine a pressure based duty cycle error based on the pressureerror.

Aspect 7 can include, or can optionally be combined with the subjectmatter of Aspects 1-6 to optionally include wherein the applied dutycycle generator is configured to combine the specified duty cycle witheach of the duty cycle error and the pressure based duty cycle error togenerate the applied duty cycle.

Aspect 8 can include, or can optionally be combined with the subjectmatter of Aspects 1-7 to optionally include wherein the pressure basedduty cycle error includes a pressure based duty cycle correction, andthe valve operator duty cycle error includes a valve operator based dutycycle correction.

Aspect 9 can include, or can optionally be combined with the subjectmatter of Aspects 1-8 to optionally include wherein each of the smartnozzles includes an associated spray nozzle.

Aspect 10 can include, or can optionally be combined with the subjectmatter of Aspects 1-9 to optionally include a master node configured forcoupling with a system pressure regulator, the master node is configuredto control the system pressure of the liquid agricultural product.

Aspect 11 can include, or can optionally be combined with the subjectmatter of Aspects 1-10 to optionally include wherein the ECU includesthe duty cycle modulator.

Aspect 12 can include, or can optionally be combined with the subjectmatter of Aspects 1-11 to optionally include the system pressureregulator in communication with the master node, and the system pressureregulator includes one or more a system pump or a pressure regulatingvalve.

Aspect 13 can include, or can optionally be combined with the subjectmatter of Aspects 1 -12 to optionally include wherein the system pumpincludes one or more of a carrier fluid pump configured to pump carrierfluid or an injection pump configured to pump injection product, and theliquid agricultural product includes the injection product mixed withthe carrier fluid.

Aspect 14 can include, or can optionally be combined with the subjectmatter of Aspects 1-13 to optionally include a sprayer control system,comprising: a plurality of smart nozzles, each of the smart nozzlesincludes: at least one control valve having a valve operator; anelectronic control unit (ECU) configured to operate the valve operator;and one or more spray nozzles, wherein the at least one control valveand the ECU are configured to control a flow rate of liquid agriculturalproduct through the one or more spray nozzles; and a duty cyclemodulator in communication with the ECU and configured to generate anapplied duty cycle of the at least one control valve, the duty cyclemodulator includes: a specified duty cycle input having a specified dutycycle; a pressure monitor associated with the at least one control valveconfigured to determine a valve pressure proximate to the at least onecontrol valve; a pressure comparator configured to compare the valvepressure with a system pressure and generate a pressure error; and anapplied duty cycle generator configured to generate the applied dutycycle based on the specified duty cycle modified by the pressure error.

Aspect 15 can include, or can optionally be combined with the subjectmatter of Aspects 1-14 to optionally include wherein the pressuremonitor includes one or more of: a pressure transducer proximate to theat least one control valve; an incrementor/decrementor configured toassign pressure values according to location of the at least one controlvalve; a system performance register having pressure according tolocation of the at least one control valve; a flow rate to pressuretransformer configured to determine the valve pressure based on the flowrate through the at least one control valve; or an operator performanceto pressure transformer configured to determine the valve pressure basedon valve operator performance.

Aspect 16 can include, or can optionally be combined with the subjectmatter of Aspects 1-15 to optionally include wherein valve operatorperformance includes one or more of movement of the valve operator orelectrical characteristics associated with movement of the valveoperator.

Aspect 17 can include, or can optionally be combined with the subjectmatter of Aspects 1-16 to optionally include wherein the ECU includesthe pressure monitor, and the ECU is configured to monitor one or moreof electrical characteristics or movement of the valve operator todetermine the valve pressure proximate to the associated at least onecontrol valve.

Aspect 18 can include, or can optionally be combined with the subjectmatter of Aspects 1-17 to optionally include wherein the duty cyclemodulator includes a pressure error to duty cycle transformer configuredto determine a pressure based duty cycle error based on the pressureerror.

Aspect 19 can include, or can optionally be combined with the subjectmatter of Aspects 1-18 to optionally include wherein the applied dutycycle generator is configured to combine the specified duty cycle withthe pressure based duty cycle error to generate the applied duty cycle.

Aspect 20 can include, or can optionally be combined with the subjectmatter of Aspects 1-19 to optionally include a system pressure regulatorin communication with a master node, and the master node is configuredto control the system pressure of a liquid agricultural product.

Aspect 21 can include, or can optionally be combined with the subjectmatter of Aspects 1-20 to optionally include wherein the ECU includesthe duty cycle modulator.

Aspect 22 can include, or can optionally be combined with the subjectmatter of Aspects 1-21 to optionally include wherein each of the smartnozzles includes an associated spray nozzle.

Aspect 23 can include, or can optionally be combined with the subjectmatter of Aspects 1-22 to optionally include a method for controllingone or more spray nozzles comprising: supplying liquid agriculturalproduct to at least one control valve at a specified system pressure;driving at least one control valve having a movable valve operator at aspecified duty cycle; monitoring valve performance of the at least onecontrol valve, monitoring includes: determining valve pressure proximateto the at least one control valve; and modulating driving of the atleast control valve according to the monitored valve performance,modulating includes: comparing the valve pressure with the specifiedsystem pressure to determine a pressure error; generating an appliedduty cycle based on the specified duty cycle modified by the pressureerror; and driving the at least one control valve at the applied dutycycle.

Aspect 24 can include, or can optionally be combined with the subjectmatter of Aspects 1-23 to optionally include wherein pressure errorincludes a pressure based duty cycle correction; and generating theapplied duty cycle based on the specified duty cycle modified by thepressure error includes generating the applied duty cycle based on thespecified duty cycle modified by the pressure based duty cyclecorrection.

Aspect 25 can include, or can optionally be combined with the subjectmatter of Aspects 1-24 to optionally include wherein determining valvepressure proximate to the least one control valve includes: measuringvalve pressure proximate to the at least one control valve; assigningvalve pressure proximate to the at least one control valve according toincrementing or decrementing of the system pressure based on a locationof the at least one control valve; assigning valve pressure proximate tothe at least one control valve according to a system performanceregister having pressure values for the at least one control valveaccording to the location of the at least one control valve; generatinga valve pressure value based on flow rate of the liquid agriculturalproduct through the at least one control valve; generating a valvepressure value based on valve operator performance.

Aspect 26 can include, or can optionally be combined with the subjectmatter of Aspects 1-25 to optionally include wherein generating thevalve pressure value based on valve operator performance includesgenerating the valve pressure value based on one or more of movement ofthe valve operator or electrical characteristics associated withmovement of the valve operator.

Aspect 27 can include, or can optionally be combined with the subjectmatter of Aspects 1-26 to optionally include wherein monitoring thevalve performance of the at least one control valve includes determiningan actual valve operator duty cycle of the at least one control valve.

Aspect 28 can include, or can optionally be combined with the subjectmatter of Aspects 1-27 to optionally include wherein modulating drivingof the least one control valve includes: comparing the actual valveoperator duty cycle with the specified duty cycle to determine a valveoperatory duty cycle error; and generating the applied duty cycleincludes generating the applied duty cycle based on the specified dutycycle modified by the pressure error and the valve operator duty cycleerror.

Aspect 29 can include, or can optionally be combined with the subjectmatter of Aspects 1-28 to optionally include wherein the pressure errorincludes pressure based duty cycle correction, the valve operator dutycycle error includes a valve operator based duty cycle correction; andgenerating the applied duty cycle includes generating the applied dutycycle based on the specified duty cycle modified by the pressure basedduty cycle correction and the valve operator based duty cyclecorrection.

Aspect 30 can include, or can optionally be combined with the subjectmatter of Aspects 1-29 to optionally include spraying the liquidagricultural product from a spray nozzle in communication with the atleast one control valve driven at the applied duty cycle.

Aspect 31 can include, or can optionally be combined with the subjectmatter of Aspects 1-30 to optionally include wherein the at least onecontrol valve includes a plurality of control valves; and driving the atleast one control valve at the specified duty cycle is conducted foreach of the control valves; and monitoring valve performance andmodulating driving of the at least one control valve are conducted foreach of the control valves.

Aspect 32 can include, or can optionally be combined with the subjectmatter of Aspects 1-31 to optionally include wherein monitoring valveperformance and modulating driving of each of the control valves isconducted independently for each of the control valves based on valvepressure proximate to each control valve, respectively.

Aspect 33 can include, or can optionally be combined with the subjectmatter of Aspects 1-32 to optionally include wherein supplying theliquid agricultural product to the at least one control valve at thespecified system pressure includes: supplying the liquid agriculturalproduct at an elevated system pressure greater than the specified systempressure; and providing the liquid agricultural product at the specifiedsystem pressure along at least one location of a sprayer boom having theat least one control valve and a boom tube interconnecting the at leastone control valve and a source of the liquid agricultural product.

Aspect 34 can include, or can optionally be combined with the subjectmatter of Aspects 1-33 to optionally include wherein the at least onecontrol valve includes a plurality of control valves distributed alongthe boom tube; and supplying the liquid agricultural product to the atleast one control valve at the specified system pressure includes:supplying the liquid agricultural product at an elevated system pressuregreater than the specified system pressure; providing the liquidagricultural product at the specified system pressure along a sprayerboom; and minimizing the pressure error at one or more of the controlvalves of the plurality of control valves according to supply of theliquid agricultural product at the elevated system pressure.

The above description includes references to the accompanying drawings,which form a part of the detailed description. The drawings show, by wayof illustration, specific embodiments in which the invention can bepracticed. These embodiments are also referred to herein as “examples.”Such examples can include elements in addition to those shown ordescribed. However, the present inventors also contemplate examples inwhich only those elements shown or described are provided. Moreover, thepresent inventors also contemplate examples using any combination orpermutation of those elements shown or described (or one or more aspectsthereof), either with respect to a particular example (or one or moreaspects thereof), or with respect to other examples (or one or moreaspects thereof) shown or described herein.

In the event of inconsistent usages between this document and anydocuments so incorporated by reference, the usage in this documentcontrols.

In this document, the terms “a” or “an” are used, as is common in patentdocuments, to include one or more than one, independent of any otherinstances or usages of “at least one” or “one or more.” In thisdocument, the term “or” is used to refer to a nonexclusive or, such that“A or B” includes “A but not B,” “B but not A,” and “A and B,” unlessotherwise indicated. In this document, the terms “including” and “inwhich” are used as the plain-English equivalents of the respective terms“comprising” and “wherein.” Also, in the following claims, the terms“including” and “comprising” are open-ended, that is, a system, device,article, composition, formulation, or process that includes elements inaddition to those listed after such a term in a claim are still deemedto fall within the scope of that claim. Moreover, in the followingclaims, the terms “first,” “second,” and “third,” etc. are used merelyas labels, and are not intended to impose numerical requirements ontheir objects.

Geometric terms, such as “parallel”, “perpendicular”, “round”, or“square”, are not intended to require absolute mathematical precision,unless the context indicates otherwise. Instead, such geometric termsallow for variations due to manufacturing or equivalent functions. Forexample, if an element is described as “round” or “generally round,” acomponent that is not precisely circular (e.g., one that is slightlyoblong or is a many-sided polygon) is still encompassed by thisdescription.

Method examples described herein can be machine or computer-implementedat least in part. Some examples can include a computer-readable mediumor machine-readable medium encoded with instructions operable toconfigure an electronic device to perform methods as described in theabove examples. An implementation of such methods can include code, suchas microcode, assembly language code, a higher-level language code, orthe like. Such code can include computer readable instructions forperforming various methods. The code may form portions of computerprogram products. Further, in an example, the code can be tangiblystored on one or more volatile, non-transitory, or nonvolatile tangiblecomputer-readable media, such as during execution or at other times.Examples of these tangible computer-readable media can include, but arenot limited to, hard disks, removable magnetic disks, removable opticaldisks (e.g., compact disks and digital video disks), magnetic cassettes,memory cards or sticks, random access memories (RAMs), read onlymemories (ROMs), and the like.

The above description is intended to be illustrative, and notrestrictive. For example, the above-described examples (or one or moreaspects thereof) may be used in combination with each other. Otherembodiments can be used, such as by one of ordinary skill in the artupon reviewing the above description. The Abstract is provided to complywith 37 C.F.R. §1.72(b), to allow the reader to quickly ascertain thenature of the technical disclosure. It is submitted with theunderstanding that it will not be used to interpret or limit the scopeor meaning of the claims. Also, in the above Detailed Description,various features may be grouped together to streamline the disclosure.This should not be interpreted as intending that an unclaimed disclosedfeature is essential to any claim. Rather, inventive subject matter maylie in less than all features of a particular disclosed embodiment.Thus, the following claims are hereby incorporated into the DetailedDescription as examples or embodiments, with each claim standing on itsown as a separate embodiment, and it is contemplated that suchembodiments can be combined with each other in various combinations orpermutations. The scope of the invention should be determined withreference to the appended claims, along with the full scope ofequivalents to which such claims are entitled.

The claimed invention is: 1-34. (canceled)
 35. A sprayer control system,comprising: a first smart nozzle, including: a control valve having avalve operator; an electronic control unit (ECU) configured to operatethe valve operator; and a first set of one or more spray nozzles,wherein the control valve and the ECU are configured to control a flowrate of liquid agricultural product through the first set of one or morespray nozzles; a first pressure monitor associated with the first smartnozzle, wherein the first pressure monitor is located proximate to atleast one of the first set of spray nozzles and is configured todetermine a first nozzle pressure proximate to the at least one of thefirst set of spray nozzles; a duty cycle modulator in communication withthe first ECU, the duty cycle modulator configured to generate anapplied duty cycle of the first control valve, and the duty cyclemodulator includes: a pressure comparator configured to compare thefirst nozzle pressure with a system pressure and generate at least onepressure error; and an applied duty cycle generator configured togenerate the applied duty cycle based on a specified duty cycle modifiedby the at least one pressure error.
 36. The sprayer control system ofclaim 35, further comprising: a second smart nozzle, including a secondcontrol valve having a valve operator; a second set of one or more spraynozzles, wherein the at least one control valve and the second ECU areconfigured to control a flow rate of liquid agricultural product throughthe first set of one or more spray nozzles; and a second pressuremonitor associated with the second smart nozzle, wherein the secondpressure monitor is located proximate to at least one of the second setof spray nozzles and is configured to determine a second nozzle pressureproximate to the at least one of the second set of spray nozzles;wherein the pressure comparator generates the at least one pressureerror based on a comparison of one or more of the first nozzle pressureor the second nozzle pressure with the system pressure.
 37. The sprayercontrol system of claim 36, wherein the first smart nozzle and thesecond smart nozzle are installed along a boom tube having a first boomend and a second boom end.
 38. The sprayer control system of claim 37,wherein the first pressure monitor is located between the first boom endand the first control valve.
 39. The sprayer control system of claim 38,wherein the second pressure monitor is located between the first boomend and the second control valve.
 40. The sprayer control system ofclaim 39, wherein the first pressure monitor is located between thefirst boom end and the second pressure monitor.
 41. The sprayer controlsystem of claim 36, wherein the ECU includes a first and a second ECUassociated with the respective first and second smart nozzles.
 42. Thesprayer control system of claim 35, further comprising a pressureregulator configured to adjust the system pressure, and the systempressure is adjusted based on the at least one pressure error.
 43. Thesprayer control system of claim 42, wherein the pressure regulatorincludes a carrier pump or an injection pump.
 44. The spray controlsystem of claim 42, wherein the pressure regulator is configured toincrease the system pressure to a system overpressure based on the atleast one pressure error.
 45. A sprayer control system, comprising: anarray of smart nozzles, each of the smart nozzles of the array of smartnozzles includes: a control valve having a valve operator; an electroniccontrol unit (ECU) configured to operate the valve operator; one or morespray nozzles, wherein the control valve and the ECU are configured tocontrol a flow rate of liquid agricultural product through the first setof one or more spray nozzles; and a pressure monitor located proximateto at least one spray nozzle of the one or more spray nozzles, thepressure monitor is configured to determine a nozzle pressure proximateto the at least one spray nozzle; and a duty cycle modulator incommunication with the ECU of each of the smart nozzles, the duty cyclemodulator is configured to generate applied duty cycles for the controlvalve of each of the smart nozzles of the array of smart nozzles, andthe duty cycle modulator includes: a pressure comparator configured tocompare the nozzle pressure for each smart nozzle of the array of smartnozzles with a system pressure and generate a pressure error for each ofthe smart nozzles; and an applied duty cycle generator configured togenerate applied duty cycles for each smart nozzle of the array of smartnozzles based on a specified duty cycle modified by the pressure errorfor each of the smart nozzles.
 46. The sprayer control system of claim45, wherein the array of smart nozzles includes a first smart nozzle anda second smart nozzle, wherein: the first smart nozzle includes a firstset of the one or more spray nozzles, and the pressure monitordetermines a first nozzle pressure proximate to the at least one of thespray nozzles of the first set of one or more spray nozzles; the secondsmart nozzle includes a second set of the one or more spray nozzles, andthe pressure monitor determines a second nozzle pressure proximate tothe at least one of the spray nozzles of the second set of one or morespray nozzles; and wherein the pressure comparator generates thepressure error based on a comparison of one or more of the first nozzlepressure or the second nozzle pressure with the system pressure.
 47. Thesprayer control system of claim 46, wherein the first smart nozzle andthe second smart nozzle are installed along a boom tube having a firstboom end and a second boom end.
 48. The sprayer control system of claim47, wherein the pressure monitor of the first smart nozzle is locatedbetween the first boom end and the control valve of the first smartnozzle.
 49. The sprayer control system of claim 48, wherein secondpressure monitor of the second smart nozzle is located between the firstboom end and the control valve of the second smart nozzle.
 50. Thesprayer control system of claim 49, wherein the pressure monitor of thefirst smart nozzle is located between the first boom end and thepressure monitor of the second smart nozzle.
 51. The sprayer controlsystem of claim 45, further comprising a pressure regulator configuredto adjust the system pressure, and the system pressure is adjusted basedon the at least one pressure error.
 52. The sprayer control system ofclaim 51, wherein the pressure regulator includes a carrier pump or aninjection pump.
 53. The spray control system of claim 51, wherein thepressure regulator is configured to increase the system pressure to asystem overpressure based on the at least one pressure error.
 54. Thesprayer control system of claim 45, wherein the array of smart nozzlesincludes a first smart nozzle and a second smart nozzle, wherein: thefirst smart nozzle includes a first set of the one or more spraynozzles, and the pressure monitor determines a first nozzle pressureproximate to the at least one of the spray nozzles of the first set ofone or more spray nozzles; the second smart nozzle includes a second setof the one or more spray nozzles, and the pressure monitor determines asecond nozzle pressure proximate to the at least one of the spraynozzles of the second set of one or more spray nozzles; wherein thepressure comparator is configured to compare the first nozzle pressurewith the system pressure to determine a first pressure error; whereinthe pressure comparator is configured to compare the second nozzlepressure with the system pressure to determine a second pressure error;wherein the applied duty cycle generator generates a first applied dutycycle for the first smart nozzle based on the first pressure error andthe specified duty cycle for the first smart nozzle; and wherein theapplied duty cycle generator generates a second applied duty cycle forthe second smart nozzle based on the second pressure error and thespecified duty cycle for the second smart nozzle.